I used to cave dive years and years ago and explore dry caves when we lived in the Missouri area. There are a ton of limestone caves there. Many aren't mapped or really marked at all, especially when you get in the bluffs along the Mississippi.

I stopped when I got stuck in a tight passage and almost drowned in a flash flood. Caves seem like these super cool places and they're climate controlled so they seemed kind of, I don't know, soft?

Then I figured out they're not and they're really really really fucking dangerous. Oh, the stupid stuff 20 year olds get up to.

Insanely dangerous, and even well marked, frequently explored caves can abruptly turn deadly even for experienced cavers. Still more terrifying is cave diving, in which explorers descend by up to hundreds of meters through winding, claustrophobic, narrow caves entirely filled with water.

At least with "dry" cave exploration, if you get stuck, you might survive up to several days with a hope of rescue, assuming you can stay hydrated and not freeze to death. With submerged cave exploration, the minute you run into serious trouble, the clock starts ticking with life lasting only as long as your air tanks. The stuff of nightmares.

This YouTube channel covers many of these accidents and incidents really well. https://www.youtube.com/watch?v=M2xs90tbEeY

The death of John Jones in Nutty Putty cave is the stuff of nightmares.

He was trapped upside down for 27 hours before dying.

https://science.howstuffworks.com/environmental/earth/geolog...

We used to joke that our student caving club was really very safe, having only had seven fatalities over the 50 years it had been operating.

In reality we had a lot of expertise and took safety very seriously. The club had always done a lot of exploration of new caves and other intrinsically tricky activities, and six of the seven deaths were in the same accident (the Mossdale Caverns tragedy of 1967). Our parties of freshers were in very limited danger being trained in well-known and well-explored caves. But still.