The Top 50 places I've been to: #2 Cenotes of Mexico's Yucatan Peninsular

Cenotes are natural sinkholes found on the flat plane of the Yucatan Peninsular. They supposedly owe their existence to a giant asteroid that hit this region some 60 million years ago wiping out the dinosaurs (google Chicxulub crater if you want to know more). Around the rim of this crater thousands of these Cenotes can be found. When the porous limestone collapsed, it exposed a giant underground aquifier.

You can spend months there, exploring all those vastly different types of Cenotes. Bring a snorkel and enjoy yourself in this natural wonderland. And if you're brave enough you can even dive from one Cenote to another as they're all connected below the surface.