Inside the Tower; Unmanned; Wonder of the World | 60 Minutes Full Episodes [37:12-40:23]

cave, this dough line is enormous. It's 450 feet above my head. In other words, about the height of a 45-story building. We stopped here with Howard Limbert, who's explored Vietnam since the 90s. When my producer and Nicole Young suggested the story, I turned her down. I said, Nick, it's a hole in the ground. What was I missing? You're missing the best adventure that happens in the world. Something no one's seen before. That's the beauty of caves. If you climb in a mountain, you can see where you go in. When you go in, you don't know what he's going to do. Your father was a caveman. He was, yeah. So he was a caveman in Scotland. Peter McNabb, the first in Sondon, has been caving since he was a boy. You grew up in a cave. Not quite, but within a mile of it. McNabb is a construction manager in New Zealand, big projects, like hospitals. But you get the sense he does that to pay for this. In all the caving that you've done, what is the closest call you've ever had? I've been stuck. I've had rocks collapsed and I've been flooded in. He was stuck a few years ago when he went headfirst into a crevice that cabers call a squeeze. McNabb couldn't back out. A partner found him and used a knife to rip away his coat to give him the spare half inch he needed. Did he pull you out by your feet? Pretty much. Yeah. You are still exploring this region? Yes, yes. We've come back every two years and we've barely scratched the surface of the caves in this area. There may be another biggest cave in the world. That could well be. Truth is, McNabb's first expedition in 2009 never reached the end of Sondon. Beyond this underground lake, he discovered a 30-story wall and ran out of time before he could scale it. We climbed it on our track and understood immediately why they call it, the great wall of Vietnam. Keep the line tight. Take in excellent. Take it in on the line. It's a 300-foot climb on slick rock with no foothold anywhere. Take in excellent scott. That's really good. Put a mic up to the corner. It's challenging enough until you realize, of course, you're doing it in the dark and it's essentially raining. The groundwater is coming from the roof. So with everything wet, you find yourself slipping back while climbing up. But our team got us up and over, drenched and a little exhausted.