Sistema Ox Bel Ha – Mexico (19/20)

The Ox Bel Ha cave system, located near Tulum, Mexico, is a close contender for the world’s longest cave title with an impressive length of 270 kilometers (167 miles). Mostly explored by divers, the system consists of flooded passages and features stunning underwater features such as crystal-clear pools and intricate rock formations. It is one of the most important underwater cave systems in the world.