This is Bushman's Hole.

On the surface, it's just an unassuming, murky green pool at the bottom of a cliff face.

Look under the water though and it changes entirely.

The water is crystal clear and it extends far deeper than the cliff face above.

In fact, it is considered to be one of the deepest known freshwater caves on Earth,

and that fact alone also makes it one of the most dangerous.

So in this video, we're going to go over the horrifying instance that have taken place here.

In early August of 1993, some of the world's very best cave divers arrived in South Africa

for a particularly special expedition.

They were there to dive a sinkhole known as Bumanzgut or Bushman's Hole, which happens

to be the third largest freshwater cave known to man.

And more importantly, they were there to set a new record for

the deepest ever cave dive. Among those invited to the expedition was South African

cave diver Bhuti Shun, who was familiar with South African Sinckels, and so his experience was

invaluable. But he brought his friend Eben Leiden along with him. Eben hadn't actually been

invited on the expedition, which initially created some concern. These types of dives, as you might imagine, are tightly controlled, so just showing up with an extra buddy seriously violated the group's protocol. It's not entirely clear, but it seems that Booty may have vouched for Eben's skill, and so the issue was dropped, and Eben was allowed to dive alongside him. It's also possible that it was allowed simply because their dive wouldn't be the actual world record attempt, as that was being left up to Sheck Exley. If you followed the channel for any length of time, you probably know Sheck Exley as one of the pioneers of cave diving. But in any case, prior to Sheck's attempt to the world record, Bouti and Eben suited up for an exploratory dive and entered the water.

From the surface pool, they made their way through the vertical tunnel toward the first bend.

Then past the bend, everything was going fine until the relatively narrow entrance tunnel opened up into a massive chamber at around the 197 foot mark or 60 meters.

Just before that point is a spot where divers can stop for a brief check-in before heading deeper. The two men stopped and all was clear for them to continue on, so Bouti led the way further down.

When he reached 197 feet, though, he suddenly noticed Eben was nowhere near him.

He looked around and then he spotted Eben's flashlight beam bouncing back and forth frantically

through the darkness as if he was desperately searching for something.

...