Cenotes!

One of my favorite things in Mexico.  There are hundreds of these in Yucatan - they are fresh water sink holes.  Some are in caves, with bats, turtles, and fish.  They are beautiful, refreshing, and tropical.  I'll add some pictures one of these days.  These were created by the asteroid that killed the dinosaurs (I also found a monument to the dinosaurs).  The asteroid hit Earth in the Gulf of Mexico, just off the coast near Progreso on the Yucatan Peninsula.  It was bad news for the dinosaurs, but great news for humans 65 million years later...  we get to go swimming in the cenotes!