The Greatest Treasure Hunts Ever! | Expedition Unknown S3 | Discovery Channel India

Trolls reveal critical clues, but to find the exact spot where the caravan was lost, we have to study the terrain as it appeared 800 years ago, and to do so, we have to see it from above. So we know where he was coming from, we know where the treasure was going to, how do you narrow that down? We use something called LiDAR, and LiDAR, basically, it's like an airborne laser system that pings these lights very fast at the ground. It gives you this snapshot of the landscape underneath the landscape. And so what did the data reveal? Well, the first thing you can see is the height differences between areas of landscape, and that's really important. That green area marks perfectly the shape of the medieval estuaries. The crossing point is somewhere between that seabank and that seabank. I think there's three or four potential crossing points that make sense. One of those crossing points, you save the best part of a day. And at this time of year, when you're on a war footing, saving a day's travel is important. That crossing point is between here and there. That's about five miles. The plane returns to the airstrip. I say goodbye to Ben and continue my journey to see how his LiDAR scans are being used to find the missing treasure. Well, Ben's LiDAR discoveries have been big news, and now various groups of archaeologists and historians are on the ground attempting to use that data to pinpoint the location of the accident. And I'm going to join them, which means I'm headed back to the Wash. I drive nearly 100 miles north to the edge of the Wash and through the medieval gates of the historic city of King's Lynn. Walking around King's Lynn is like stepping through a portal into the past. Between the soaring cathedral, ancient streets, and time-worn bridges, it's easy to imagine King John himself rolling through here. King's Lynn has been on the map since the Middle Ages. It used to be known as Bishop's Lynn, and in King John's time, it was a thriving port city. It's also one of the few towns in England that doesn't hate King John, and that's because he actually granted the city a charter, which gave them certain rights. In fact, they're so sympathetic to King John here in King's Lynn, they actually erected a statue of him. Or of the Burger King. In fairness, it's very hard to tell the difference. I'm here to meet with one of the UK's most successful metal detectorists named Gary Drayton, who's asked me to meet him at the place where all treasure hunts officially begin and end, the local pub. Hey, Josh. Nice to meet you. How you doing? How are you? Great, thanks. Do you have an idea where you think King John's treasure might be? Yeah, well, thanks to these new LiDAR readouts, we've got a lot of new areas that have opened up to us. And have you investigated in these places before? No, I haven't, but we are going to be. Gary and I make our way to meet up with fellow treasure hunter, Charlie Field. What are you guys getting into here? This is probably a crossing. What we should do is metal detect first, and then that way we can use the dredge in the areas that look the most promising. And the dredge basically is just suctioning up the mud? Yeah. So you're going to find things, tiny things, which you wouldn't find with a metal detector as well. Now, you might think that after the waters recede, the king's men will just come back down to the wash and recover the treasure, but it's not quite that simple. The thick mud here swallows anything and everything that touches it. So while some of the larger pieces of treasure might be recovered, without future technology, the rest of it will be impossible to find here in the 13th century. Thankfully, Gary and Charlie have brought all the modern day treasure hunting essentials, including a dry suit that I'm assured will keep me toasty warm. Help me. Okay, snug as a bug, we're suited and booted. And don't open this zip underwater, is that correct? Yeah. Okay, got it. Perfect. We arrive at the wreck site and immediately prepare to dive, but we have to move fast because a report says that serious weather is headed our way. Okay, we're heading up to the wreck. Okay, here we go. Because the ship burned before it sank, nothing is left of its wooden hull. But the rest of its metallic cargo should still be intact. The wreck is very shallow. She only sits at about 10 feet of water. It's amazing it took so long to find it. She sat here for 300 years, untouched and unseen. Suddenly, three centuries after its tragic fate, we come face to face with the ghostly remains of a real-life pirate ship. My quest for Captain Kidd's treasure has taken me to the Dominican Republic, and the exact spot where Kidd's ship, the Caida Merchant, burned and sank. Its anchors may be the key to finding a hidden trove of Kidd's loot. Look at that. It's gorgeous. It's heavily encrusted, but you can clearly make out that it's a cannon. Absolutely awesome. Cannons like these had barrels over 9 feet long, and the Caida Merchant had 30 of them, mounted and ready for a fight at the drop of a hat. You did not want to mess with this ship. Hey, Josh, come over here. This is the main department of the wreck. Copy that. Look at that. There's one there and another. They're all just piled up on top of each other. The way the cannons are laying, I think they're in the holes. We found the cannons, so hopefully the anchors will be close by. We fan out to look, and sure enough... Josh, look. We got an anchor. Look at that. You can clearly see the arms, and you can see where the shank goes back here. No doubt about it, that's a huge anchor. Absolutely fantastic. A telltale sign of the anchor's age is the absence of an iron cross beam. In Kidd's time, those beams were made of wood, which means it rotted away long ago. The weather above the surface is turning darker, and we may only have scant minutes before conditions turn for us down below. John hurries to take precise measurements of the anchor. It's like 40 feet, more or less. I will load you down in the beginning with this rope. Just so I understand this, you're going to pull me out of this hole using that consumer power drill? Yeah. It's working. You'll be surprised. Yes, I will be surprised. OK, let's see what happens. The shaft was concealed beneath ancient stonework, and because no one has been down there for hundreds of years or more, we can't be sure the air is safe, or that there is any air for that matter. We send down a meter to test how much oxygen there is for us to breathe. We don't have any poison gas, just the air is a bit thin. A bit thin? It's right on the line. It will be more thinner because we are more people down. Once we get the green light to proceed, we tape our cuffs at the wrists and ankles to keep spiders and scorpions from doing their own excavations. Finally, it's time to go. Holy moly. I begin my descent through 3,000 years of history. Here we go. Hoping that at the bottom lies a pathway that leads directly to the Ark of the Covenant. Biblical archaeologist Scott Stripling and I are descending into a tunnel beneath one of the most ancient and sacred places in the world, the Old City of Jerusalem. See you on the other side. See you down there. He's hoping this trip could lead to the impossible-to-access area beneath the Holy Temple Mount, where some believe the Ark of the Covenant has been hidden for millennia. Okay. How's it going down there? Oh, it's going great. Very old blocks all the way down. Does the stone change from the top to the bottom? It looks pretty consistent. The stone on the top is definitely 1st century, so if it's consistent all the way down, then we know that this is a 1st century shaft. Copy that. Looks like it's opening up a little bit down here. Looking good. Okay, I'm definitely at the bottom, lowering. There's a passage! You're kidding me! How wide is it? It's very narrow, Scott. It's only about 2 feet across. Coming down. An extremely cramped passageway leads into the darkness, unexplored for centuries. It means Scott may be right, and this could connect to a larger tunnel network leading under the Temple Mount. Pick it up, Scott. I'm in a coffin down here. Okay, I'm on the ground. I wedge into a small opening so he can lead the way. Right behind you, Scott. All right, here we go. We start to push forward into the tunnel. It's pitch black down here, and the air feels thin. We're joined by one of Scott's team members, who's equipped with supplemental oxygen. Notice how the roof is changing. These pavers that have been laid in here 2,000 years ago, I'm positive now that this is a drainage system from the 1st century. Any idea how far back it goes? Well, further than I can see, we're going in the direction of the Temple Mount. Okay, let's see where this thing goes. The size of these stones above us is incredible. Oh, they're massive. Remember, we're about 40 feet under the modern city of Jerusalem right now. Some of the stones are holding up better than others. Looks like the lentil stone actually cracked. Yeah, it is broken. It looks unstable, so don't touch it. Copy that. As you're coming in, stay low. Stay down. There you go. All right, you made it. Things don't get any more comfortable as we move in the direction of the Temple Mount. The further we go, the tighter the tunnels seem to narrow. Yeah, I'm pretty much hands and knees at this point. This is incredible, but also incredibly claustrophobic. This is as dangerous a place as I've been in a long time. The ancient tunnel is unstable, the air is barely breathable, and we're down here with Jehovah-knows-what. Oh, spiders. Why did it have to be spiders? But at the end of it could be the Ark of the Covenant. So there's no thought of turning back. Oh my goodness. What'd you find? You're not going to believe what we've got here. What do you got? I can't believe what I'm looking at. The signature of Conrad Schick, dated 1863. Look at that! Conrad Schick was a famous 19th century archaeologist, one of the few to explore under the Temple Mount before it became too volatile to dig. You can see clearly here, C. Schick. Now the date's a little rubbed out, but if we look back here, his companion has dated it 1863. That is outrageous. Can you believe that this man had the presence of mind 150 years ago... To graffiti the wall? To actually tag the wall so that we could find it and show it to the world. Oh man, I knew I should have brought my can of spray paint. You're looking at history right now. This is a real confirmation that this is one of the tunnels that he discovered and surveyed. Well, it's positive proof. I mean, as an archaeologist, we dream about having inscriptions for evidence. Yeah. You couldn't get any more clear than this. This is awesome. This is so awesome. All right, man. Nice work, buddy. Excellent. OK, let's see where this tunnel goes. All right. Could his signature mean that these tunnels connect to those in the Temple? We have to push on, even as the walls close in on us, until there's no further for us to go. Josh, we've come to a collapse. Blocked off? It's blocked off. Looks like the tunnel actually does keep going, but another shaft has collapsed in. Anywhere to sneak a camera through there? I don't see any way to get a camera through. It looks unstable. In the future, maybe we'll be able to raise the money and come back and actually excavate this tunnel and see if it goes the rest of the way toward the... Oh, dude, look at this. Look at that. Oh, dude, look at this. Look at that. Oh, wow. I mean, that is legit, right? Yeah, that is... I mean, that goes down way deeper than I thought. Yeah, it does. Can you get us down? Yeah. And back up again? Sure can. Let's do it. All right. Luckily, Darren doesn't just hunt for treasure. He also rock climbs. So we unpack helmets, harnesses, and carabiners. Soon, we've got an anchor in place, and we're ready to lower ourselves into the unknown. All right, let's do this. The cave entrance is a long plunge straight down. So getting in will require a tricky rappel into complete darkness. Looking good, man. How's it look down there? It's getting pretty icy down here. Just take it slow, man. No worries. All righty. Are you okay? Yep, I got it, man. You okay? Slippery down there. Darren, you down? I made it down. It's looking great. All right, man, I'm coming down. Once Darren reaches the bottom, it's my turn. It's slippery as can be down here. I was prepared to deal with just about anything in my search for plumber's gold. And this is just pure ice. But subterranean snow was not something I had anticipated. It's looking good. Okay. This place is incredible. There's just so much going on down here. Let's see what's down here, man. Look at how big this place is, dude. It is a huge cave. Oh, my God. I mean, this room must be 30, 40 feet tall. Now that we're down here, what's the plan? I think the plan should be looking for any kind of evidence of people being down in here. Uh-huh. Just to see. Yeah, anything man-made. Okay. And then I also have a metal detector with us. Okay, cool. Well, it looks like this may go back over here to the right. Yeah. And then at the end of this chamber, it definitely looks like it keeps going, yeah? Yeah, for sure. Okay, let's get the detector up. Okay. You check over there, I'll go back here. All right, sounds good. All right, come on. Deep in the mountain, it should be simple for Darren's metal detector to register signs of the treasure. The challenge is that the caves are seemingly endless. The gold could be anywhere. Hey, Josh, I got something, man. What do you got? I don't know what it is, but it's loading it out. It's right here. Yeah, there's something here, dude. There's something metal here for sure. There could be something hiding in there. Look at that big old metal can. It's been down here a long time. Long time. Nothing too fancy, but it's still fun. Oh, but look, man, this is... Someone's been here for sure. It is super old. So now we know that folks were down here, and they were down here a long time ago. Question of the day, what's this doing down here? Yeah, who was here and what were they doing? We continue sweeping the cave, but it turns out this place is huge. And with just flashlights, we're lost in a maze of tunnels. But Darren has packed a state-of-the-art tool to give us an edge in the darkness. That is the thing from Ghostbusters that catches ghosts, correct? No, not quite. It's actually a handheld LiDAR unit. It's like a rangefinder on steroids. It shoots out 90,000 laser pulses per second. I'm sorry, per second? Per second. This thing is doing super accurate 3D mapping in real time. This is honestly one of the coolest things I've ever seen. All right, let's see it work. Darren flips a switch, and away we go. The device is silent. Honestly, if it wasn't for the spinny part, I wouldn't even know it was on. But for two long, cold hours, we trudge through the cave looking for clues and letting the LiDAR scanner do its thing. Super muddy here, careful. Oh, yeah. When we're finished, the result is this. A fully rendered 3D map of the entire cave system. I'm astounded by the Bruce Wayne-level technology, but also how little of this place we were actually able to see with our own eyes. Wow, that's cool. It is so cool. So this really shows us that there might be another passage over here that's worth exploring. That looks like it shoots off, yeah? Yeah, it does, for sure. No, we haven't been there yet. Okay. Let's go check that out. Yeah, let's do it. All right. I love this thing. I'm definitely stealing it from you. Yeah. Deep underneath Montana, treasure hunter Darren Wedding and I are scouring for evidence that Old West Sheriff Henry Plummer used these caves as a hiding place for his cache of stolen gold. A high-tech scan has led us to a concealed chamber, and now we've found a literal sign that we might be in the right spot. Look at this. What? Look at this. Plummer, 1865. 1865. Look at that. I got some bad news here. This is two years after his death. He died in 1863, right? Yeah. And I think he had one M in his name, not two. Yeah, it's spelled P-L-U-M-E-R. Wrong spelling, wrong year. Different Plummer. Different Plummer, I guess, but what a crazy coincidence. That is definitely really weird, man. I mean, that's nuts, right? That's literally a million to one. Even though the date isn't right, we continue to search the chamber. In the end, we found the name, but not the gold. The mayor's chief investigators lead me out of the city center and along the banks of the Busento River to an anonymous-looking farm outside of town. All right, first question. Why are we here? So, basically, this site clearly matches the description that King Gallery was buried at the foot of a hill where a river used to pass. Right. And if you can hear it... Yeah, so there's a river over there. You can hear a river passing over there, which actually used to be much wider, and it used to cover all this area. This was all river? This was all the river. All this farmland was underwater? Yes. So, we actually did some analysis using LIDAR. Using LIDAR? Yes. LIDAR is a technology that uses lasers to create a 3D topographic map. It can penetrate foliage to reveal evidence of where the ground has been dug up or shifted in the past. And we can see in the LIDAR result that we have an anomaly here. Right. These bumps. Exactly. Wow, look at that. There's something there. Yes. And so what do you think that is? This shows that here there was some sort of an activity. The ground has been dug up. This is the anomaly we're trying to look for. Okay, so we've got a place that matches the description. Exactly. And technology telling us that something could be here. That something could be here, yes. Well, I like that. This is the perfect place to look. Okay, well, let's start looking. Joseph and Andre can't do it alone. So they've called in reinforcements. And these guys brought along some serious toys. Buongiorno. Franco and his team are from a company called Prospezione SRL. We're going to be doing an electro-tomography. It's basically an analysis of the subsoil level using electrical pulses. So you're going to electrocute the ground. Exactly. Let's do it. Allora. Hammer, rods, check. Okay. Different types of soil, not to mention a buried goth king, have different levels of resistance to electric pulses. So to virtually see beneath the ground, we insert a series of metal rods. And that means it's hammer time. And once they're all wired up, we send an electric current through the rods that should confirm if there's anything unusual under the surface, as the LiDAR scans suggest. And now connect these together? Yes. What could possibly go wrong? Look at this thing. Here we go. With everything wired up and electrified, we gather around the computer. Okay. And we wait for the software to crunch the data. And after a few minutes, the results are in. Oh, what's that? What is that? We have an anomaly here. That's an anomaly. Great. So let's dig. We prepare to excavate using a piece of machinery that looks something like the love child of an ATV and a rocket launcher. Okay. What the Sam Hill is this thing? It's a mobile drilling machine. And we use it to take core samples of the subsoil layers. Aha. Just to look at the cross section and see what's there? Exactly. The machine cores down into the earth and collects a cylinder of soil that offers a snapshot of different layers and different periods of history. Do you want to try it? He said if you wanted to drive it. To put it in position? Yeah, to put it in position. Yes, yes. Very much so. First of all, we have to put the helmet. Okay. Should I sit here? Okay, here we go. Oh my God, this is amazing. All right, the controls look pretty self-explanatory. Oh yeah, listen to her hum. All right, are you ready? I notice you're backing up a pretty fair distance here. All of you seem to have gotten much farther away. Where to? There? Okay. Here we go. Oh yeah, oh yeah. Oh boy. She's smooth. I got it. All right. Yep, I got it. I got it now. It's like riding a bike, if your bike is the machine from the journey to the center of the earth. That's it? Okay, now what? This one forward? Oh, come on! Yes! This thing's awesome! Oh my God, this thing's a transformer. I'm in love with this machine. Piano, piano. Uh-huh. Once the initial hole is made, they attach a core sampler to the drill and send her back down. ABC, always be coring. Take a core and we're going to see sort of a core section of the subsoil layer. Awesome. All right, here comes the core. They crack open the cores and lay out the samples in a tray. Beautiful. Next, we'll dig through the dirt for proof that this was once part of the river. Okay. And to determine if the anomaly we imaged could be the tomb of King Alaric. Okay, George, maybe sand? Yes, sand. And does this feel like material that was at one time underwater? On the riverbed, yes. This is all sand that comes from the riverbed. So we're definitely in a river layer. Exactly. Okay. Knowing this was a riverbed is an encouraging sign that the tomb could be nearby. And this depth, this is close to the right time period for Alaric? Yes. Okay. Oh, Josh. We have something. Oh! What is that? Hey, Josh. It's copper? It looks like copper, yeah. Oh, it's marked. Look at that. There's a design on it. And there too. You see that? Yes. It's beautiful. What do you think this was? Could have been a piece of a brooch, a belt, for example. Right, right, right. The markings on it are amazing. And do you think this could be from the 5th century? Could this be that old? Could even be older. Wow! That is stunning. To find a fragment of an artifact like this inside a core is rare indeed, and it will need to be cleaned and studied further. But there's no doubt that this is a promising area. So, now what? So, we have very important clues, so now the idea is to set up a dig to really discover what was here, what happened here. Who knows what else could be right underneath us? Yes. Maybe Alaric. Hope. Let's hope for it. This is awesome, guys. Awesome work. Okay. Really cool. Step one of our investigation is letting a sonar system scan the darkest recesses of the lake. This should provide a never-before-seen 3D image of what lies beneath the surface, allowing us to pinpoint anomalies on the lake's floor. Hopefully one of them will be a box of German gold. Okay, sonar's up, and we are already recording now. The system may look home-spun, but it's absolutely bleeding-edge tech. Richard is using a multi-beam sonar system together with dual GPS receivers and a motion reference unit to pinpoint targets on the lake's floor to centimeter accuracy. This system has revolutionized exploration surveying, and almost immediately the computer starts spitting back results. So, what you're looking at here is the bottom where it's there, a very strong signal. Right. That means it's a very hard bottom, really. And things like this, what is this on the bottom here? You know, I don't know. But that's the sort of thing we'd want to send the divers down to if it's still within their depth range. Wow. And so for now, though, we just keep collecting data. That's it. All right. We continue our methodical pass across the lake to let the sonar scan for anomalies on the bottom. Sometimes you're looking at things that probably nobody's ever looked at. I'll bet there's places in this lake nobody's dived there, so nobody's ever seen it. Man on the moon type stuff. It is. Yeah. We complete our scan, and I navigate us back to the shore where we reconvene with the team. We eagerly await for the computer to process the data in hopes that it will uncover possible locations for the lost treasure. How did the number crunching go? Number crunching has gone really, really well and very surprising. That's the hole in the middle. Right. And around the outside of that, you can see the actual shape of this lake. Is that underwater? That's all underwater. That's what you do not see when you stand there looking out across that lake. Oh, my God. It's huge. So that's what it looks like in two dimensions, and this is what it looks like in three dimensions. That's crazy. That's phenomenal. That is awesome. It's beautiful. You know what it is? That's the first time we've really seen what this lake looks like. The scan reveals, for the first time ever, a complete picture of the mysterious Ochocoto. The lake actually widens like a cone underneath the cliffs and is much larger and deeper than anyone expected. This is really extraordinary. In terms of depth, what are we looking at here? Well, at the very, very bottom, you're down about 300 feet. That's incredible. Can you go inside of it? Let's go. Let's go where the divers would go without all that paraphernalia. That's insane. And now we're on the seafloor. Are these some of the hits we saw in the sonar? Exactly. So, I mean, we've got a map, but what we're really trying to do here is find these anomalies, find the targets that the divers can go down to efficiently, get them right to a spot where there's something unusual. So there's this whole new perimeter inside the lake, in the bottom of the lake, that maybe hasn't been completely searched before, where things could have rolled down into. Absolutely. Chris, in terms of sorting through these targets, how do you attack this? These sites here, there's a couple of hits which we could definitely reach with conventional, normal, you know, scuba gear. Do you think I might be able to get down to those? I think you could. And what about these deeper targets? Could you guys reach those targets? We could reach those targets, yes. Okay. So should we go down there and see what these targets actually are? Let's go. Let's go. Let's go diving. First, we'll investigate the targets that lie just over 100 feet down. Later, Chris, Evan, and Johan, who are certified technical divers, will use specialized underwater gear to investigate the deeper hits. Okay. So this is where things get real. The sonar has given us some really exciting hits, but as Richard says, it's all about getting eyes down there. So this lake is very dangerous. It's very deep. This will be a particularly deep dive for me, so I'm feeling anxious, but really excited to get down there and see what's actually on the bottom. Okay, Josh, we've got that comm system up here, so we'll be able to talk with you. Sounds good. All right. Stay in touch. Great. Have a good dive. Thanks very much. To guide us in the murky water, we drop what's known as a shot line down to the area of the first sonar targets. Okay, we are here. Copy that. Heading down the line. Chris, temperature is dropping here. This is the thermal climb. It's still going to get chilly up. Okay. We're passing 30 meters. Copy that. 30 meters. Okay. We are touching down on the bottom here. Excellent. You should be down about 34 meters and descending along the slope to the sonar target. Copy that. Be careful. If you disturb that sand, it can get really murky very quickly. Copy that. I'm trying to stay off the bottom. We make it down to the area where Richard's sonar revealed several anomalies, and as the sand settles, my flashlight catches something amazing. We've got a cannon here! This is one of the cannons first spotted by Pheo in 1984. I'm blown away by this magnificent piece of living history. This is the first one. At six, seven meters, we have a second one. The colonial German-era cannons are proof positive that soldiers dumped their arms right here in Lake Ochocoto. That part of the legend is undeniable. We go down here. Oh, my God. I'm on the Mediterranean island of Corsica on the hunt for evidence of a multimillion-dollar treasure. Legend says that gold and jewels looted as part of the campaign by Nazi commander Erwin Rommel were taken out of North Africa and hidden somewhere on this island. A group of local explorers believe it's concealed in an underground lake in the city of Bonifacio. And there's only one way to get there, by rappelling down more than 200 feet inside a crumbling well. Oh, my God. That goes all the way down to the ocean level? Yes, almost 200 feet. The well is unstable and is ringed by a hand-carved spiral staircase. And why aren't we taking the stairs? They're collapsing. Oh, they're more dangerous than going down that hole? More dangerous. The staircase has been condemned and the well is strictly closed to the public. Almost no-one alive has laid eyes on the cavern below. Is this floor stable? No, no, it's very dangerous. So nothing is safe? Nothing is safe. That's my new motto. Okay, here we go. I'll see you at the bottom, guys. Okay, the floor is super rotted, and I'm headed down, but I'm not looking down because it is absolutely horrible. Oh, God. Don't look down. Don't ever look down. It's bottomless. This is a bottomless pit. Okay, it's opening up. It's opening up into a chamber. Okay, definitely water underneath me. I'm going to drop a couple of chemlights. In the dim light of my glow sticks and headlamp, I find myself dangling above the cave floor with no sense of just how big this room really is. Oh, my God. I'm in the grotto. Okay, I'm down Unbelievable. Marianne is the next to drop into the well, and she carefully descends through the darkness to the cavern floor. Guys, she's down. This is outrageous. Yes, I told you. It's unbelievable. Look at it. It just goes and goes. After Marianne, the scuba gear is lowered. I got it. Then the rest of her team. This has been months in the planning, and they arrive ready to get to work. Welcome. First of all, we're alive, which I'm very excited about. That's a good thing. Now what do we do? Let's get the scuba gear on, and then we go underwater. Does anything live in this water? There is a six-foot eel. Okay, come on. Let's go diving. In the glow of our dive lights, the flooded caverns appear like an eerie dreamscape, though touching the fine sand on the bottom can fog the entire chamber in an instant. This is beautiful down here. So clear. I'm trying not to kick up the silt. We hover through the cave, looking for any evidence of the wooden crates that an eyewitness claimed was hidden in an underground lake. But we soon see that we're not the only ones poking around down here. Whoa, there's an eel. Thank God it's not six feet long. Marianne and her team lead on, but the walls seem to be closing in around us. Okay, so it looks like that's the end of the line in here. It's just nothing but rock. Is this it? Is this the end, you think? It looks like it keeps going. It looks like it keeps going? Okay, let's stick our noses through. We'll see if anything's in there. Marianne has spied what looks like a passageway into another chamber, but since it appears to be entirely underwater with no air pocket above and with visibility deteriorating, we proceed cautiously. I see it. There's a way through. The opening is tight, so we squeeze through in single file into a second chamber. It's possible we're the first people to swim in here since World War II. Look, a bottle. Unlike the first chamber, this one contains artifacts, a clear indication that someone has been down here before. Looks like a metal fuel canister. Maybe from a boat. As we push on, we notice what appears to be another air pocket above us, so we ascend to see exactly where we are. Look at that. It's a new chamber. Wow. Unbelievable. Beautiful. Yeah, it's amazing. Look at the stalactites. That's incredible. Why are they yellow? It's because of the sulfur. Sulfur? Yes. Wow. That is something else. The room is huge. It's absolutely incredible. Nobody comes here. It's very difficult. Looks like some dry land over there. Let's see if we can get up there. Our investigation moves to solid ground. We're looking for anything that backs up the eyewitness account. Marianne? Looks like maybe a piece of wood. Where? Oh, yeah. Let me get over there. Yeah, definitely wood. Looks like a plank. It has old nails in it. It's really rotted. I mean, it's literally just disintegrating in my hands, so whatever it is, it's been down here for a very long time. We fan out to check every corner of the cave for anything else that might be down here. Guys! Guys, come here. Look at this. It's a box for sure. With a team of explorers led by Marianne Bolzanger, I'm in search of a lost Nazi treasure beneath the island of Corsica off the coast of France. Guys, guys, come here. Look at this. It's a box for sure. Look at this. Careful. It's a box. Oh, look at that. Is there anything in it? It's just disintegrating. There's nothing in it. I mean, that has been down here for ages, I assume. Yes, I think so. Why is that even in here? We motor toward Attila's target zone, islands, where he thinks the Huns damned a section of the mighty Danube. Give me kind of a lay of the land out here. This is the Great Hungarian Plain. Attila's land. The other side, it is the Roman Empire. So we are between Attila's land and the Roman Empire. Wow. So how do you search that much river? Well, you need time and technology. And this is what we have, a side-scan sonar. Side-scan sonar works by dragging a sensor behind us as we cover the area. The sensor will send sonar pulses to the riverbed and receive real-time topography of the bottom of the Danube. Look. Kind of squared off. A lot of things. A lot of things right there. Wow. Yes, but this could be just maybe a fish. Right. The sonar is already picking up lots of small debris on the bottom. But having used this type of technology before, I don't expect to get a promising hit anytime soon. Turns out, I'm dead wrong. Look. Oh. What's that? It's big. I'm in the middle of the Danube River in Hungary along with a maritime archaeologist. Using side-scan sonar, we're searching for signs of the casket of Attila the Hun, which is said to be crafted in layers of solid gold, silver, and iron. And we just got a hit. Look. Oh. What's that? It's a wreck. It's a wreck? Yes. That's a wreck. That's a shipwreck. Yes. Not a big ship, but a ship. Come on. It's 10 meters long. And you have it on GPS so we know where it is. Yes, yes, yes. This is why I love sonar. On land, archaeology, digging in a trench with a toothbrush, sonar, you just fly over it and it doesn't lie. It's astounding. So in terms of Attila, though, what would we be looking for? The tomb of Attila and the dam downstream of the island. These are artificial objects. Huge, big earthwork. On the sonar, you could see first the dam which they built. Even if it's destroyed, some evidence for the dam is existing, and you can see with the sonar. After the tomb, which is a big rectangle with very strong reflection. We log the location of the boat and continue our scan. For the next several hours, we go up and down the banks looking for additional clues. And finally, the sonar senses something sizable beneath us. What's that? Oh, look at this. What is that? Boxes. Very big. Whoa, whoa, whoa. What is that? It's a large and rectangular object. One meter long. Oh, look at here. And more. More. One, two, three, four. That's crazy. What is that? Well, there is only one thing to do. Dive? Yes. Let's get in the water. We plunge into the frigid Danube and head down to the rectangular-shaped object spotted by the sonar. The muddy bottom of the Danube is really churning, so our eyes are useless. We decide to employ the low-tech method of swatting randomly with our arms, which turns out to be surprisingly effective. I'm on top of the object. I can feel it, but I can't tell what it is. The object is way too heavy to carry, so we attach an inflatable lift bag to pull it off the riverbed. Then we use the rope to drag the object over to a dock on the nearby island, where we can pull it ashore. Holy... Okay, careful. Don't get under it. Oh, my God. It is huge. Definitely metal. Filled with mud. I don't know if it's filled with anything else, but, look, this looks modern up here, yeah? Yeah. It could be even Second World War. That's what I was thinking, yeah? We're looking for a metallic coffin, but this box, while intriguing, just isn't from the right time period. This is World War II, yeah? It looks like. Though it's not Attila's tomb, this container is a piece of history. This section of the Danube saw brutal fighting between German and Allied forces in World War II. We've likely just dredged up a remnant of the Nazi presence here in Hungary. Not the tomb of Attila the Hun, but a piece of history nonetheless. Yeah. That's incredible. Since we don't have a Hun-sized army to pull the chest all the way out... Back down into the dark. ...we let it sink back into the depths, where the golden tomb may also be lying in wait. Dr. Toth will be back to scan the Danube on another day. But after my time on the river, I realize that if the Huns did want to keep the grave a secret by burying Attila underwater, then it's a plan that's working. But not everyone believes he's in the water. The next morning, I push my Soviet rust heap the 30 miles to Budapest. I'm here to look at some research that suggests Attila was buried on land, and to take in the sights of one of Europe's most beautiful cities. I first came here in the 90s. Communism had collapsed, the economy was in ruins, and if I'm being honest, the whole city felt as though it was cloaked in a depressing shade of gray. But what a difference a few decades makes, because color has returned to Budapest, and on the streets you can feel an electric energy, a new generation that is returning this city to its rightful place as one of Europe's coolest capitals. In short, Budapest is back. As I head to my meeting, I make sure to stroll through Memento Park, a repository of all the statues from the country's communist era. All your favorites are here. Lenin, and of course Joseph Stalin, or at least his boots. The only intact remains of an 85-foot likeness that was torn down in the failed 1956 uprising. The love of statuary seems to be a Hungarian obsession. Around Budapest are other statues. Sorry, I don't mean to bother you. Thanks. Peter Falk, in costume as Columbo. Ronald Reagan, in costume as a president. Perfect, you were great. And a statue of one of the most important writers in the country's storied past, Anonymous. No, it's not a joke. It's actually a specific anonymous writer who penned the oldest and most significant book in Hungarian history, the Gesta Hungarorum. It's the definitive chronicle of the origins of the Hungarian people, and it may contain an important clue in the hunt for Attila the Hun. The original 800-year-old manuscript is kept in Budapest Grand Central Library, where I'm meeting with Dr. Borbala Abrasanski. She's going to give me an exclusive look at this priceless medieval manuscript in a special humidity-controlled chamber. So, does this book give us a history of Attila the Hun? No, no, it's a history of King Arpad. King Arpad. And Arpad is later than Attila, yes? Yes, later his grand-grand-grandson. King Arpad, who ruled about 450 years after Attila, is considered the first king of Hungary as we know it. Arpad was obsessed with Attila, and leveraged his name and lineage for his own political power.