what a topic,

but just in case you feel like diving a hole in the jungle in Mexico, Tulum, see a quite old and real jaguar bone (leg) in a stalagmite cave, see your own torch light reflecting in a, depending on weather, clear or cloudy, thermocline (where sulfur rich cold water meets pristine clear "sunhot" water) and think you might actually enjoy that,
I would recommend the so called "Pit"...

http://www.youtube.com/watch?v=ZO0orBIrrdg

The experience is not at all comparable to a UV colored and by all means psychedelic healthy reef, quite different, some would say boring, but it's definitely my definition of Xibalba as close as it gets...

Couldn't resist, just really fitted the topic
"Mayan Wonders"

I agree. here's some pics from my visit to the cenotes near Tulum.

or in other words,

just to "keep it real",
you can enjoy the beautiful surroundings of tulum stay at (no advertisement intended) nunu's place and visit coba.
You can dive the "pit" with cenote dive center but you probably wont get the "grand tour", at least we didn't. It's WELL worth it though...

really nice pics... ^^ paradise

beautiful..
simply, beautiful

Breath Taking...I can only imagine being able to afford to go somewhere so beautiful. Life hasn't been kind to me regardless of my efforts and how much positive karma I put out. But its great to know there are places like this....Not that I'll be able to see them but just like TV show like Earth I can still appreciate what I do see. You guys are really blessed to able to see these type of places.

Wow those pics are mesmerizing Olympus.. That is pretty cool the sulfur keeps it clean and must provide a good environment for the organisms that make the water blue. I think they have bacteria in pools similar to that in yellowstone national park hot springs. Simply beautiful I will definitly try to dive there some day. How was the dive did you go?