The Sacred Cenote at Chichén Itzá is also littered with jade fragments, which were burned and then dropped into the water by ancient inhabitants. When scorching jade hits the water it shatters, making sound that reverberates thought the ritual complex.

https://en.m.wikipedia.org/wiki/Sacred_Cenote

So is scuba diving them! Down you go into a going black hole, swimming through amazing caves (don’t let go of the rope!), the out the other side in a different cenote. Surreal experience