When you're learning to cave dive, one of the first things that you learn is that you may very well die in there. Most of the training focuses on systems, skil

When you're learning to cave dive, one of the first things that you learn is that you may very well die in there. Most of the training focuses on systems, skills repetition, and understanding and using redundant systems - folks getting into cave diving typically are already extremely experienced divers who if anything need only some minor skill tweaks - most cave instructors will not take on students who don't already have significant open water technical diving experience (multiple tanks, mixed gas, rebreathers, decompression, wreck, etc). A running joke is that the lost line drill (where you're placed intentionally off of the guide line and have to find it without a mask/light/visibility) is the most punctual cave task you'll ever do - you have the rest of your life to get it right. Here's a few good books on it (non-affiliate links): Caverns Measureless to Man by Sheck Exley (the father of cave diving): https://www.amazon.com/Caverns-Measureless-Man-Sheck-Exley/dp/0939748258 https://www.amazon.com/Caverns-Measureless-Man-Sheck-Exley/d... The Darkness Beckons by Martyn Farr: https://www.amazon.com/Darkness-Beckons-History-Development-Diving/dp/1910240745/ref=zg_bsnr_290109_1?_encoding=UTF8&psc=1&refRID=Q1DCCDZ0MMB4N2SCBYBQ https://www.amazon.com/Darkness-Beckons-History-Development-... Beyond the Deep by Bill Stone (the Tony Stark of cave diving): https://www.amazon.com/Beyond-Deep-Deadly-Descent-Treacherous/dp/0446527092 https://www.amazon.com/Beyond-Deep-Deadly-Descent-Treacherou... The Cenotes of the Riviera Maya by Steve Gerrard (patron saint / mapper of Yucatan caves): https://www.amazon.com/Cenotes-Riviera-Maya-2016/dp/1682134016/ref=tmm_pap_swatch_0?_encoding=UTF8&qid=&sr= https://www.amazon.com/Cenotes-Riviera-Maya-2016/dp/16821340... This is more of a map and explanatory notes but gives great insight into the complexity of it. Currently there are 2 systems that almost all cenotes are part of in the Yucatan, and there's some really interesting work going on trying to link the two. Current work is going on at about 180m depth through a number of rooms at the back of "The Pit", and there are multi-day expeditions going on trying to find the linkage.