Cities Of The Underworld: The World of Freemason Underground Societies (S1, E10) | Full Episode

[suspenseful music] DON WILDMAN (VOICEOVER): Nine of the 56 men who signed the Declaration of Independence were members of a mysterious brotherhood-- one that was behind almost every major event in our nation's history, the Freemasons. And beneath the streets of two of America's oldest cities lie the keys to understanding the Freemasons' power and influence on the birth of this great nation. Wow.

DON WILDMAN (VOICEOVER): From a Masonic water world few know exists-- My foot is literally stuck in the [bleep]. . This is not on the tour.

This is the crypt. DON WILDMAN (VOICEOVER): --to a maze of tombs and escape tunnels buried under Boston, even a forgotten death row military prison in Philadelphia seen on TV for the first time-- Oh, my god. This is so cool.

W. H. Howe.

He is the prisoner who was actually executed at the gallows outside. Yeah. DON WILDMAN (VOICEOVER): --the symbols of Freemasonry can be found everywhere around Boston and Philadelphia.

But the truth behind this brotherhood can only be found underground. Yeah. There we go.

DON WILDMAN (VOICEOVER): We're peeling back the layers of time on "Cities of the Underworld, Freemason Underground. " [theme music] [music playing] Buried beneath the streets of big cities like Boston and Philadelphia are the untold secrets of America's rebellious founding fathers-- secrets that helped topple an empire and build a nation. For over 200 years, they've been built on top of and forgotten.

But the clues left behind from these dark days all have one thing in common. They link the greatest achievements in American history to members of an elusive secret society. They're called the Freemasons, and little is known about them.

From buried water worlds beneath Philadelphia to tunnels running below Boston's North End, their secrets change the world as we know it. And today they're about to be revealed. The Freemasons had their hands in many parts of the American Revolution.

Some say the Constitution of the United States was so influenced by the ways of the Masons, the founding of our nation has been dubbed the Masonic Experiment. The actual origins of the Freemasons are shrouded in mystery. But we do know that in the Middle Ages they were an exclusive group of master artisans who passed on their craft-- or building skills-- to fellow Masons accepted into their group.

But for reasons no one can be sure of, Masons in Scotland began accepting non-artisans. Buildings suddenly became much more than just structures. They were symbols in stone.

When the first Freemasons came to the New Colonies, they went from building structures to building a nation one city at a time. [rock music] One of the most famous Masons was Paul Revere. Revere and many of Boston's other citizens refused to be ruled by the British, and were the spark that lit the fires of revolution.

In April 1775, tensions between the British Empire and the American Colonies had grown to a fever pitch. American Patriots operated secretly among British troops by using the narrow streets and subterranean tunnels right here in Boston's North End. But when they got wind the British were coming, they had to rely on the sacred loyalty of an ancient brotherhood.

DON WILDMAN (VOICEOVER): The Freemasons gave new meaning to the idea of the underworld. Membership allowed revolutionaries to operate underground, even while carrying out military actions high above the city. Before I went down, I had to go up to the very spot the Masons made famous.

Soaring 191 feet above Boston, the steeple of Old North Church was the highest point in the city. It gave the conspiring Masons a commanding and strategic view. Reverend Ayres.

Good morning. Welcome to the Old North Church. Thank you.

Thanks for meeting me. DON WILDMAN (VOICEOVER): The Old North vicar, Reverend Stephen Ayres, gave me special access to the spot the Masons' plan was put to action. Follow me up to the bell ringing chamber.

DON WILDMAN (VOICEOVER): At about 10 o'clock on April 18, 1775, Freemason Robert Newman, church caretaker, climbed the stairs and lit two lanterns, signaling that the British were headed for the colonists' weapons depot in Concord, while Paul Revere was on his way to Lexington to warn John Hancock and Samuel Adams. Here we are at the top. Oh, yeah.

Fantastic. This is where it all began, huh? It's a spectacular view from up here.

Oh, man, look at this. Oh, it's great. Wow.

360 degrees, all of Boston around us, huh? STEPHEN AYRES: This was the tallest point in the colonial times. DON WILDMAN (VOICEOVER): Leaders of the growing rebellion, John Hancock and Sam Adams, were in hiding.

Out of reach of the British, they were well connected with other revolutionaries because they too were Masons. STEPHEN AYRES: Most of the American Revolution, at least in Boston, was either organized at Masonic meetings or in the local taverns, in a back room. DON WILDMAN (VOICEOVER): The Masons used this church's steeple to help the cause of the Revolution.

But the church also has a subterranean story to tell. And Reverend Ayres was going to take me to it. All right.

Well, now that we've shown you the steeple, let me show you the tombs. DON WILDMAN (VOICEOVER): Hidden beneath this church is something few know about-- an underground world of the dead. [suspenseful music] As we come into the old tombs, note the sign.

Watch thy head. There are lots of pipes in here. Yeah, wow.

Yeah, OK. So this is the crypt. This is the crypt.

DON WILDMAN (VOICEOVER): In less than 40 tombs there have been hundreds bodies-- from wealthy admirals to the working class. Some of the dead in this crypt were even killed during the Revolutionary War, in the Battle of Bunker Hill. So Patriots, members of the King's Army, and Freemasons may have been buried side by side.

The crypt is large. But even so, there were times when these tombs would be so packed with dead bodies it was unbearable down here. This is not the most sanitary form of burial.

If you go on the outside of the church, you will see vents running along the base of the church on both sides. That was to air out the basement. Just imagine the smell of moldering bodies down here on a hot summer day.

DON WILDMAN (VOICEOVER): Over 1,000 bodies have passed through here over the centuries. Some were surely Masons, carrying their secrets along with them. But Reverend Ayres told me the subterranean space wasn't initially built to bury people.

The tombs were built over a series of years here. It wasn't designed originally to have tombs. The north end was filled with smuggling tunnels during the colonial era.

You wanted to avoid the revenue agents. As a matter of fact, there's a story that some folks sent-- put signals in the steeple to signal which, you know, ship to go to which wharf to offload some of their cargo into a smuggling tunnel before the revenue agents would show up. We believe that there are tunnels that led into this basement or quite close by.

DON WILDMAN (VOICEOVER): Many of the smuggling tunnels have since been sealed up or have collapsed. But as Reverend Ayres took me back upstairs, I got a glimpse of the strange contraband that once passed through them. STEPHEN AYRES: Those angels were given to the church by a member of the congregation, Captain Thomas Gruchy.

He, by profession, was-- among other things-- a privateer. He lived just up the street. And actually, underneath his house is an old smuggling tunnel.

As a privateer, of course, that meant he was a licensed pirate-- Right. --which means that those are stolen angels. So you got pirate's booty right here in the church.

Pirate's booty right here in the church. [laughs] DON WILDMAN (VOICEOVER): So a pirate actually used underground tunnels to smuggle his stolen booty. And it all went down right below this church.

But how did he even know about the tunnels? [suspenseful music] Reverend Ayres says there's this guy across the street from the church here that has a smugglers tunnel from the Revolutionary Period. It used to belong to the pirate who gave the cherubs to the church.

Let's go check it out. [rock music] DON WILDMAN (VOICEOVER): Sonny Mirabella's house was just a few blocks from Old North Church. Rumors of tunnels used by everyone-- from the Freemasons, to Pirates, to bank robbers-- run rampant in the neighborhood.

A sealed off hole in Sonny's basement only adds fuel to the fire. Hey, Sonny. Hi.

Yes? Don Wildman. Hi, Don.

Reverend Ayres told me to come over. Oh. How you doing?

My pleasure meeting you. Thanks for having me over. DON WILDMAN (VOICEOVER): Sonny got right to business-- Be careful.

Watch your step. All right. It's an old building.

OK. DON WILDMAN (VOICEOVER): --and led me to his crowded basement. It's a basement.

Yeah, this is a basement. This is-- this is it. This is the tunnel.

OK. This is the original. SONNY MIRABELLA: That's the-- this is all the original brick.

This is the same size brick they used on the Old North Church. Uh-huh. So the guy that had the angels in the Old North Church-- Captain Gruchy.

--lived in this house. Yes. And he bought the contraband coming from the waterfront.

So he's a big time smuggler, this guy. Oh, he was a thief. [laughter] DON WILDMAN (VOICEOVER): The north end tunnels are more than an urban legend.

Some locals say there are entrances to the tunnel system in just about every cellar in the old neighborhood. Even though it no longer allows access to subterranean Boston today, use of these passageways may have continued until well into the 20th century. 11 men robbed an armored car company headquarters and stole nearly $2.

7 million. It was the perfect crime. And law enforcement searched high and low for the missing cash.

Believe it or not, my new friend Sonny actually became a suspect. This is a true story. OK.

I get a knock on the door like you just knocked. There's two or three big guys out there, and I says, can I help you. They says, we're the FBI.

I says, what can I do for you. He said, we want to see the tunnel. I says, how do you know I have a tunnel.

He says, we know everything. [laughs] So I took 'em down. I said, it's been blocked.

He said, I want to see. I showed 'em. They looked.

He says, OK. I says, you know who did it? He says, no.

I thought you guys knew everything. Yeah. So you're not doing any smuggling these days.

SONNY MIRABELLA: No. My smuggling days are over. [laughter] DON WILDMAN (VOICEOVER): The FBI did finally apprehend all 11 accomplices in the Brinks robbery.

But their stash of $1. 1 million disappeared forever somewhere in Boston's seedy underground. From the lost Brink's cache and Captain Gruchy's pirate booty to the secret stomping grounds of Paul Revere and the Freemasons, Boston's soil is full of secrets.

And this city is only just the beginning. [rock music] I'm in Philadelphia, ground zero for the American Revolution. Since the beginning, this country was built by rebels, misfits, members of secret societies like the Freemasons.

So how did this ragtag group of Patriots defeat the world's most powerful empire? Well, there's only one place you can still find the answers-- the underworld. DON WILDMAN (VOICEOVER): But before I went underground, I was granted an interview with Ronald A.

Aungst, who holds the same title as Ben Franklin once did-- Grand Master. Grand Master. Good to see you.

How you doing? Welcome. Thank you for having me.

Oh, my pleasure to have you. Incredible building. DON WILDMAN (VOICEOVER): The temple itself is an amazing structure-- one of Philadelphia's most iconic buildings-- and is covered with Masonic symbols.

But Freemasonry and its symbols have reached far beyond the halls of its grand lodges. They're seeing eye sign can even be found on the dollar bill, along with Mason George Washington. While symbols like the eye or the Mason compass can be seen all over the US, the initiation ceremonies for the brotherhood are held in secret.

As secretive as they are, they're just a process, a procedure. It's nothing different than when one is baptized in the church. DON WILDMAN (VOICEOVER): But it's a procedure only for the eyes of the Masons.

And it actually links them to the ancient Temple of Solomon. Solomon's master builder was a man named Hiram Abiff. He was a Master Mason, and his three apprentices desperately wanted to know the secrets of his craft.

They were tired of waiting, and plotted to force him to tell his secrets or else. One day, each demanded the guarded information. And each time Hiram refused, an apprentice hit him over the head.

The third blow killed him. Hiram's death is reenacted in today's Mason initiation ceremonies. Only after the new Mason pretends to die, he is resurrected through the power of the Masonic Grip.

The Grip is a secret handshake known by all modern day Masons. The Masons are believed to not only be linked to the Bible, but also to the Knights Templar. This ancient order of powerful Christian Crusaders were persecuted and fled to England and Scotland.

Many said they hid underground, becoming stonemasons as a cover for their true identities. Some say the Freemasons still possess the Holy Grail that the Knights Templar took with them to Scotland. Today there are over 4 million Masons in the world, 2 million in the United States alone.

And this exclusive fraternity continues to inspire and mystify the world. If you're a Mason we have three degrees. We have apprentice, we have the fellow craft, and we have the Master Mason degrees.

And those were the same thing as far as construction of the temple. So from those times, we then transposed them to a more modern culture of now, instead of building temples, we build men. DON WILDMAN (VOICEOVER): And 230 years ago, George Washington, Ben Franklin, John Hancock, Paul Revere-- men built by the Freemasons-- were literally pushing the buttons of revolution.

[upbeat music] As the capital of the breakaway colonies, Philadelphia was a prime target for the British. To defend the city from attack, city leaders called upon two famous Freemasons. George Washington was named General of the Continental Army, and Ben Franklin was in charge of defenses around the city.

So when the British attacked, the rebels were ready. DON WILDMAN (VOICEOVER): Before they were rebels, the Freemasons were builders. And most people have no idea that they had a hand in one of the most important forts of the American Revolution.

It's called Fort Mifflin, or the Fort that Saved America. It all started when Benjamin Franklin's first job was to complete the construction of a fort that would defend Philadelphia against attack. Today this fort sits in the shadow of Philadelphia's airport.

But even archaeologists had no idea what else was hiding there. And for the first time ever on television, we've been given access into a newly discovered piece of American history. Gentlemen.

How are you doing? Hello, Don. Lee, nice to meet you.

Hi. How's it going? Hey.

Thanks for having me. DON WILDMAN (VOICEOVER): I met with Lee Anderson and Andrew Fearon, the team of experts who recently helped unearth another world beneath Fort Mifflin. Their discovery is so new, I was among the first to ever be allowed down.

This place is incredible-- We think so. Yeah. DON WILDMAN: --hidden here off the highway.

LEE ANDERSON: Best kept secret in the country. DON WILDMAN (VOICEOVER): Its best kept secret was not the fact that Fort Mifflin actually changed the course of the Revolutionary War or that the great battle that took place here actually kept the British at the mouth of the river, allowing General George Washington and his troops to regroup at Valley Forge. The best kept secret was, in fact, buried underground.

So how did you find this place? Well, it was actually the site manager had-- was mowing the lawn. And, actually, part of the ground had given away and the soil kept om-- Right here.

--yeah, was continually displaced. So this is a tunnel system under here? Yeah.

DON WILDMAN (VOICEOVER): Thanks to something as simple as a lawnmower, this entire unknown section of Fort Mifflin was discovered after being buried for over 130 years. The find is so new, that no one knows exactly what went on down here or how it's managed to stay intact and hidden for so long. Basically, we've got a hole underneath there that leads to the entrance of-- of what we're calling Casement 11.

And you had no idea this was here. Absolutely no idea. DON WILDMAN (VOICEOVER): Casement 11 lies underneath the original Fort Mifflin.

It's believed that while the Masons were spearheading the Revolution in the barracks above, this subterranean space was supplying them with ammunition. But that's only the beginning. Can we-- we lift this off?

Yeah, if you'd help me just get this guy. You can set him back here. This is so cool.

DON WILDMAN (VOICEOVER): Archaeologists have just started clearing away the debris. Oh, my god. Look at that.

Watch your step. DON WILDMAN (VOICEOVER): But if they keep digging, Casement 11 could link up with an entire underworld of storage that provided munitions to the barracks nearly 15 feet above. But this was much more than an underground storage depot.

Later it was actually converted into a prison for America's hardcore criminals and POWs during the Civil War. On your belly, huh? ANDREW FEARON: Yup.

Here we go. Wow. It's really tight.

ANDREW FEARON: Careful. Oh, I see it opens up totally. Yeah.

Oh, my god. This is so cool. DON WILDMAN (VOICEOVER): The discovery is so new, no one can be absolutely sure what this room was used for.

But here's how they think it got buried. The prison is thought to be part of the original fort design from 1771. There are five subterranean rooms all supported by brick arched ceilings.

These rooms were initially used for munitions storage. Later, gun mounts were built above the room to defend against enemy threats from the river. And during the Civil War, these munitions rooms were turned into a prison.

But once the war was over, the entrance was filled in over time, and the prison was forgotten. [eerie music] ANDREW FEARON: So we'll just walk through here. Just be careful and mindful of the inscriptions off to the right.

OK. DON WILDMAN (VOICEOVER): The inscriptions were from prisoners who served time down here. Incredibly, they've been left untouched since the late 1860s until now.

Unbelievable. What are these inscriptions? Oh, I see right here.

ANDREW FEARON: So you can see these were some of the prisoners. DON WILDMAN: Oh, they're like graffiti. ANDREW FEARON: Bernard.

Yeah. We can see here, Bernard, Devon Company, 81st Cavalry. DON WILDMAN: Huh.

And what would you think was the age of this? ANDREW FEARON: Well, some of them are dated. So I think the one up here, for instance, is dated 1864.

Mm-hmm. And there's-- we've got Henry Bradley, July 1864, and some other ones down there. DON WILDMAN: We are among the few that have seen this writing since the Civil War.

You've got it. Wow, that's amazing. DON WILDMAN (VOICEOVER): But there's more.

One particular inscription tells of the bleak existence of the men who were imprisoned here. ANDREW FEARON: Wait, hold on. You've got to see this inscription here.

Oh, my god. It's so clear. Yeah.

Shun this place, oh man, whomsoever thou art. To be good is to be happy. Well, he'd learned his lesson, apparently.

ANDREW FEARON: Yeah. DON WILDMAN: Look at this. It's like a movie prop.

Yeah. It's in perfect condition. And this-- remember, this wood hasn't seen the daylight, so it's-- DON WILDMAN: It never faded.

Exactly. ANDREW FEARON: Yeah. It's been in a little time capsule.

This is pretty advanced woven metal for this time, isn't it? ANDREW FEARON: Yeah. It's absolutely-- You didn't go to Home Depot and get your screening.

No. No. Jeez, it's amazing.

[music playing] DON WILDMAN (VOICEOVER): So nearly a century after master Mason Benjamin Franklin helped finish this fort during the Revolutionary War, it was used as a prison during the Civil War. Deserters, POWs, and murderers-- for some, this was death row. So we can now enter what we think is William Howe's cell.

DON WILDMAN (VOICEOVER): William Howe was no ordinary prisoner. He was a Union soldier during the Civil War-- a hero who rallied the troops and proudly carried his flag at the Battle of Fredericksburg. Despite his efforts, they lost the battle.

And Howe and 1,000 other soldiers became disillusioned and deserted. Desertion was a major problem during the end of the Civil War, and the army had to do something about it. They used Howe as an example.

And after three weeks in captivity here beneath Fort Mifflin, they hung him in the prison yard just above. He was the only prisoner executed at Fort Mifflin during the entire Civil War. Ironically, exactly 142 years to the day after his ceremonial hanging, Howe's subterranean prison was discovered beneath the ground.

ANDREW FEARON: We know that William Howe signed his name up here. Another excellent job of penmanship. W.

H. Howe. He is the prisoner who was actually executed-- ANDREW FEARON: Yes.

--at the gallows outside. Yeah. Yeah.

Oh, man. [sighs] That is heavy. It is.

You know? DON WILDMAN (VOICEOVER): Buried beneath a freshly mowed lawn, Andrew and Lee had stumbled upon the actual foundations of the Freemasons indestructible fort. It was just a small clue into the beginnings of this secret society-- a society that both literally and figuratively helped to build our nation.

[upbeat music] [ominous music] DON WILDMAN (VOICEOVER): For a group of rebels to take on the British Army, they needed both manpower and money. The Freemasons had both. Master Mason Ben Franklin used that money to complete Philadelphia's Fort Mifflin.

Today the fort's located just off the airport. But 230 years ago, it was a key stronghold during the American Revolution. Wow.

That's amazing. Unbelievable. DON WILDMAN (VOICEOVER): I had just been one of the first to enter the newest discovery beneath this fort.

But there was more lying beneath the soil. It was at this very site that 400 volunteer Patriots held their own against the British for over 5 and 1/2 weeks. But how did they do it?

How were the Patriots able to survive the barrage of British artillery for so long? The answer was underground. [suspenseful music] Wow.

This is the largest of six in here. And we're under about 10 feet of dirt. DON WILDMAN: Wow.

This is amazing. This is all original 18th century construction. LEE ANDERSON: Late 18th century.

Yes. It would have been used as a barracks in case of another siege. It would hold about 120 guys.

DON WILDMAN (VOICEOVER): These barracks were built to last. But the Masons didn't lay the first brick. Instead, it was the British.

And when they began construction of the fort to protect their largest colonial city, they never could have imagined that just a few years later Fort Mifflin would be in the enemy or Freemason hands. It all happened in 1776. The Revolutionary War was in full swing.

And under Freemason Ben Franklin, colonists took over the fort. America was ready for war, and Fort Mifflin would help them win it. The thickness of its outer walls ranges between 6 and 10 feet, which allowed it to take endless direct hits from ships in the bay.

In fact, these walls survived the largest bombardment ever seen by the North American continent. And during those bombardments, the rooms we were in served an essential purpose. So in a-- in a time of danger, battle, this would be the alternative barracks.

It would. It would be the place where the soldiers can keep out of the bombardment, which they could have used in 1777. OK.

'Cause you're actually living inside the wall here, basically. You are. You're pretty safe.

Back then, cannonballs didn't explode. Most of 'em were solid shots, so they couldn't get through here. DON WILDMAN (VOICEOVER): But thanks to the genius of the colonists, it would take a lot to actually reach the fort.

Their first line of defense were basically booby traps lining the bottom of the river. These were 30-foot square boxes crossed by timbers. Iron spikes were then fastened to the timbers.

The boxes were then sunk into the river with 30 tons of stone. The Hope was that British ships would have gashes ripped into their hulls as they passed over them. The second line of defense was this fort.

Its walls were up to 10 feet thick, and were enlarged by the colonists when they took it over from the British. The fort appears to be designed in the shape of a pantograph. It's a tool used for copying plans or maps.

And the sides created useful angles that allowed the greatest range of fire for the troops. But there are other rumors about the fort's unique shape. The pantograph is also linked to the Freemasons' compass and square symbol.

Could the Mason heavy government that commissioned Fort Mifflin have been sending a message? Some say by building this fort in the shape of a pantograph, they leave no doubt who built both the city of Philadelphia and the new nation they would soon govern. And this isn't the only time the Freemasons have literally left their mark.

There are even theories that link the Masons with landmarks in Washington, DC. The intersection of five major roads form a pentagram, or five pointed star, with the White House at its southernmost tip. This location also links up with another Freemason emblem, the compass and square, similar to the shape of Fort Mifflin.

The US Capitol building sits at the hinge of this compass. But what actually went on in this room? What are these holes in the wall?

Those are actually gun ports. Oh, really? So those would face out.

Oh, yeah. They're all over the place here. ANDREW FEARON: They're strategic.

It would be very hard to shoot out these. Yeah. I'm sure they-- They'd have wanted to be able to shoot in, so-- You're not gonna win a battle from in here.

No. No. You're just gonna wait it out.

Yeah, OK. DON WILDMAN (VOICEOVER): 230 years ago, I would have been standing among 400 men. They were cramped inside for over a month.

The temperature dipped well below freezing. Supplies ran low. And the sleeping situation was just as bad.

So this is, like, a-- generally the size of 'em. LEE ANDERSON: It's exactly the size. You can see-- People back then were so short.

LEE ANDERSON: Yeah, that's a fallacy. [laughs] LEE ANDERSON: What they-- yeah. What they did was they-- Their feet really came out this way.

LEE ANDERSON: They slept sitting up. Oh, really? Yes.

They thought it was better for their health. DON WILDMAN: No kidding. Yes.

It wasn't until later near the 20th century that people started laying straight on their back. Yeah. Are you the only person in this country that knows that?

I had to come to Fort Mifflin to find that out. LEE ANDERSON: [laughs] [suspenseful music] DON WILDMAN (VOICEOVER): By fending off the British, Fort Mifflin changed the course of the war. But Fort Mifflin is just the beginning of the legacy the Freemasons left behind beneath Philadelphia.

Just a few miles away is the Mason inspired maze of tunnels that few realize exists. [upbeat music] In the late 18th century, Philadelphia was booming. It was the largest city in the country, and in desperate need of a clean source of fresh water.

The solution city planners came up with was an engineering marvel. No city in the world had developed a water system like this since ancient Rome. DON WILDMAN (VOICEOVER): Philadelphia was home to one of America's most famous Masons, Grand Master Ben Franklin.

Franklin, like most Masons, was a man of great power and wealth. And he was determined to use his status to make his city a better place. He willed 1,000 pounds to the city of Philadelphia, insisting that part of it be used to build a municipal water works.

This system of clean water, that allowed Philadelphia to grow into the city it is today, was not only the brainchild of Master Mason Franklin. It was also designed by one-- Freemason Benjamin Latrobe. Believe it or not, Latrobe also worked on the White House and the US Capitol.

But it was his Philadelphia water works that helped revolutionize the way cities ran. And over 200 years worth of Mason inspired water tunnels still remain beneath the streets. [traffic sounds] Hey, Ed.

Hey, Don. DON WILDMAN (VOICEOVER): I met with Ed Grusheski, an expert on the Fairmount Water Works. Great to have you here.

Look at this view. Yes. This is a perfect location to see the entire site.

For most of the 19th century, the Fairmount Water Works was the major pumping station for the city of Philadelphia. DON WILDMAN (VOICEOVER): Frederick Graf, Latrobe's apprentice, designed Fairmount Water Works in 1805, improving on Latrobe's system, which could no longer meet the needs of the city. Today Fairmont is the best example of how the Masons inspired the building of this city.

[music playing] Ed took me through the guts of the building, where until 98 years ago Philadelphia still got its water supply. It was like a time capsule dating back almost 200 years. But that's not all.

This system was way ahead of its time. And its remains are still here. ED GRUSHESKI: In the building we're going into, when it was completed, it had three huge turbines operating pumps that pumped water up to the reservoir.

DON WILDMAN (VOICEOVER): Deep beneath the engine house, the 3,000 foot long tunnel was a part of the original water works, and I got special access. I'm gonna go down and check out these tunnels that delivered the water to Philadelphia in the old times. Hey.

Hey, you're gonna need this, Don. Thank you very much. ED GRUSHESKI: Yeah.

It gets dark down there, huh? ED GRUSHESKI: It is, indeed. Yeah.

So this is where the water was coming in 1851. This is an actual 1851 brick floor. But this bedrock represents the fact that this building has been here since 1812.

This is the original foundation for the original building. It's been around for a while. DON WILDMAN (VOICEOVER): The water works project was continuously changing.

Toward the end of its life. It was even turned into a sewer. But the first version goes back to 1801, and that's the one that was a Freemason design.

It was an ingenious plan that brought water from the Schuylkill River into a canal dug through bedrock. From there, the water went to a steam driven pumping station, where it was lifted to an underground brick conduit and delivered by gravity to a pumping station in Center Square. Graff made this innovative design bigger and better, and I was inside that system.

This is the intakes for the water to go up to the pump, which is on the other side of this wall. I see there's a gate here and everything. Wow, what's all this?

This is the old cast iron or something, I guess. There's another one here. And right through here is the pump house, and there it is.

That's the original pump. Wow. It looks like modern age.

It's amazingly modern. So this would have been all filled with water, and it would have come from down in this part here. I'm gonna go down here and take a look.

I see. Wow. Here is actual water, 2 feet deep groundwater.

And this tunnel back here goes-- keeps on going. It's an old sewer from 1920. So it was 1851 here, and then 1920 down here.

And they used it actually for open sewer. I got to go check this out. I'm gonna need some waders and a stronger light.

[upbeat music] Yeah. There we go. OK.

All right, well, this is the fun part of my job. I have no idea how deep that silt is. Oh, yeah, it's nice and solid.

Let me see. This is so cool. So you can see this is the 19th century right here, the stonework.

And that, as well, that brickwork. This is the original flume tunnel that used to bring the water right in. Now, this has been a totally refitted tunnel.

And you can see the original water gate right there. But new work-- this poured concrete coming from the 1920s, when it was changed into a sewer. But I have no idea what's back here.

Yeah, here we go. This is all groundwater. This is no longer a flowing tunnel.

Hello! Wow. The silt is, like, a foot deep underneath of this, very soft, clay-like.

My foot is literally stuck in the [bleep]. . So this is not on the tour.

[laughs] DON WILDMAN (VOICEOVER): I was nearly 20 feet beneath the streets, inside the water works that made this city possible. And the people above me had no idea. It ain't pretty.

Oh, it's really stuck. You can see the housing for the whole turbine. It's huge.

And this would have been where this turbine and the blades would have come right down here. And the water would have brushed through here, turning these blades. DON WILDMAN (VOICEOVER): In the end, over 5.

3 million gallons of water were pumped through here each day, compared to the 7,500 gallons from the original Mason design. And this is just the end of the tunnel that they sealed off with railroad ties, it looks like. DON WILDMAN (VOICEOVER): Someone had sealed up this old tunnel.

But beyond this, it snakes for miles underneath the homes, businesses, and streets of modern Philly. The water works closed down for good in 1909. But these very tunnels remain, a glimpse into the foundations of our nation.

But Philadelphia and Boston aren't the only American cities that were literally built by the famous secret society. Beneath the streets of a sleepy New England town are clues from the Freemasons' most secretive and deadly days. [ominous music] DON WILDMAN (VOICEOVER): The Freemasons have played their part in fighting for America's independence, and in shaping the cities that emerged.

They have been linked to everything from the Knights Templar to the Revolutionary War. But that's just the beginning. Just outside of Boston, another stunning piece to the Freemason puzzle has been discovered inside an ordinary house.

This time it's a possible link to the Underground Railroad. [suspenseful music] The American Revolution wasn't the only time Americans were forced to operate in secret. In the 1800s, a massive network of abolitionists secretly transported Southern slaves to freedom.

With thousands of lives and the fate of a nation at stake, there was only one place to go-- underground. DON WILDMAN (VOICEOVER): And this small town was center stage for America's newest fight for freedom. The Underground Railroad made an important stop here en route to Canada.

While the underground was just a figurative name for many networks established to carry slaves to freedom in the North, here it actually went underground. And today these houses in Concord still sit directly on top of links to the secret past. Few people know that the Freemasons played a major but hidden part in the fight against slavery.

In fact, Mason Benjamin Franklin was a leading abolitionist. Here in Concord, Massachusetts, I was about to see an eerie reminder of America's darker days, unearthed accidentally during the renovation of this home. Hey, John.

Hi. John Chateauneuf knows Concord like the back of his hand. He's a local resident who's been exploring this small town's underground for years.

In 1922, when some restoration work was done on this building, they had removed a section of wall and a section to get to a chimney. And they found this room that was hidden. And research revealed that it was, in fact, used on the Underground Railroad.

Wow. Let's take a look, huh? OK.

DON WILDMAN (VOICEOVER): The building is now an art gallery. But few realize that hidden behind the fireplace is a secret room, where hundreds of slaves would have stayed on their way to freedom. [suspenseful music] Wow.

Look how small it is. Jeez. DON WILDMAN (VOICEOVER): Amazingly, this room concealed within the walls of this former home is only 3 foot by 6 foot, and doesn't have much headroom.

There are no windows, and it's cold. DON WILDMAN: In this little space they would have come up and stayed for-- for the evening or whatever, before they were moved on to the next station in the railroad. JOHN CHATEAUNEUF: Typically, what would happen in the middle of the night, perhaps, someone would come along with a wagon, pick up who was ever being hidden here.

And they would move west toward West Fitchburg, where they would bring them to a train that would head north to Canada. DON WILDMAN (VOICEOVER): The fact that this secret space was uncovered at all is Incredible. But it's those who met in the house that have opened up a Pandora's Box.

This beam up here has these designs. What's-- what's going on with that? JOHN CHATEAUNEUF: Well, this beam was uncovered during restoration work up on the third floor.

The designs on here, they suspect, have some connections to the history of the Masons in Concord. DON WILDMAN (VOICEOVER): The designs on this beam are believed to be the work of the Masons. But exactly what the carvings mean is still a mystery.

Does this Mason carved beam prove the Freemasons built this subterranean escape route? We know that in 1802 this house was, in fact, a meeting place for the Masons. But skeptics warn that the cryptically carved beam could just be coincidental, and could have been used to build the room after the Masons left here.

But one thing is for sure. The Freemasons-- specifically the African-American lodges called the Prince Hall Lodges-- were heavily involved in the Underground Railroad. The Prince Hall Lodges would have been ideal stops along a slave's escape to freedom.

They had secret hiding spots. But, most importantly, they were already a secret society and had the perfect clandestine infrastructure to pull off such a dangerous operation. And just like the Freemasons used symbols to communicate during the Revolution, stops along the Underground Railroad actually had a secret system of codes used to help people identify safe houses.

If there was a quilt stitched with a house with smoke coming out of its chimney hanging on a clothesline, that meant that house was a safe house. A white ring of bricks around the top of a house's chimney meant the same. And various geometric patterns stitched into displayed quilts helped guide slaves to freedom, and into rooms like the one I was standing in.

But how did slaves actually get into this hiding place? Some say these hidden rooms were connected by underground tunnel systems. JOHN CHATEAUNEUF: The access to this room was through a cave that came into the house.

DON WILDMAN: Below our feet. We have it-- it would be below us. And the entrance to that cave is out in the ridge out back.

DON WILDMAN (VOICEOVER): But that's not the half of it. A ridge of caves just a few feet away from these homes dates back to the 17th century. The caves were initially built as separate storage areas for each house.

But during the abolitionist era, some speculate that they were, in fact, connected and used to help the slaves move to their freedom. These connections proved to be the perfect hideouts for slaves on the Underground Railroad. Oh, my god.

Look at that. Now, this is-- Wow. --the only remaining opening in the ridge that we know of at this time.

Wow. It's really a tight space. I'm gonna take a look down in there.

Wow. It's really, really small. JOHN CHATEAUNEUF: You know, Don, you're probably the first person in there in about 70 years.

DON WILDMAN (VOICEOVER): From this small cave, escaping slaves would crawl through an underground tunnel across the backyard, under the house, and finally to the hidden room by the chimney. There they might get a meal or they may not. Racism persisted even among those dedicated to eradicating slavery.

Then, after a few hours, it's through the tunnel and out the cave again. But, logistics aside, there was a real human aspect that was hard to ignore. There's all of about, I don't know, three feet of space.

It is amazing and poignant to think of scared people being brought here in the night and asked to keep quiet or else, stashed in here until they can be secreted away to another room, where they're also kept quiet and fed until they're moved on. It's amazing and dehumanizing, but that's how it was done. Whew.

Incredible. DON WILDMAN (VOICEOVER): The Underground Railroad carried over 50,000 slaves to their freedom in Canada. Later, many former slaves returned home, finally citizens in the Land of the Free.

Few are aware of the role the Masons played in this chapter of American history. [upbeat music] Today the Freemasons continue their legacy of silence-- one that has lasted for centuries. It's hard to calculate just how much the secret society of the Freemasons changed the world we live in.

And as residents of Boston, Philadelphia, and Concord walk the streets of the cities the Masons help to build, they have no idea how close they come to clues hidden all around them-- clues that lie both above ground and below.