Try Spelunking in the Sistema Huautla
Sistema Huautla is a cave system made up of numerous caves and caverns. It is the largest in the Americas at almost a mile deep and more than 45 miles long, and the system encompasses waterfalls, lakes, tunnels, and galleries. It has been explored by spelunkers from around the world since 1964.
Location
Huautla de Jiménez, Oaxaca, México
See map