Babur's Alcove, Kandahar, Afghanistan

A cliff cave below Crystal Mesa west of Hamilili Point in Petrified Forest National Park, Arizona, United States of America, North America

Aboriginal Wandjina cave artwork in sandstone caves at Raft Point, Kimberley, Western Australia, Australia, Pacific

Aboriginal Wandjina cave artwork in sandstone caves at Raft Point, Kimberley, Western Australia, Australia, Pacific

Aboriginal Wandjina cave artwork in sandstone caves at Raft Point, Kimberley, Western Australia, Australia, Pacific

Aboriginal Wandjina cave artwork in sandstone caves at Raft Point, Kimberley, Western Australia, Australia, Pacific

Aboriginal Wandjina cave artwork in sandstone caves at Raft Point, Kimberley, Western Australia, Australia, Pacific

Porous sand stone rocks on Jalandhar Beach near the south pole point in Diu, India, Asia

Aboriginal Wandjina cave artwork in sandstone caves at Raft Point, Kimberley, Western Australia, Australia, Pacific

Grand Canyon viewed through a rock cave below Lipan Point on the South Rim, Grand Canyon National Park, UNESCO World Heritage Site, Arizona, United States of America, North America

Swimming at Cenote Ik Kil in Yucatan, Mexico, a natural pit, or sinkhole near Chichen Itza. Yucatan Peninsula, Quintana Roo, Mexico. Ik Kil was sacred to the Mayans who used this cenote for both relaxation and ritual services centuries ago.

Cenote Ik Kil in Yucatan, Mexico, a natural pit, or sinkhole near Chichen Itza. Yucatan Peninsula, Quintana Roo, Mexico. Ik Kil was sacred to the Mayans who used this cenote for both relaxation and ritual services centuries ago.

Gran Cenote de Tulum in Yucatan Peninsula, Quintana Roo, Mexico. There are thousands of cenotes dotted all over Mexico���s Yucatan Peninsula, and their existence is as much a defining characteristic of the region as is the distinct geological feature from which they result. Once revered by the ancient Mayans as sacred wells, they are now magnets for tourists, adventurers, and explorers alike.

Echo Point Ruins, about 1000 years old, Monument Valley, Arizona, USA, America

A cave explorer overlooks camp for the night from a high vantage point in Hang En, Phong Nha Ke Bang National Park, Vietnam.

Two cave explorers walk through a section of cave tunnel deep in heart of the mountain. At this point in the cave the floor was

Dramatic Sunrise At Cave Point With Brilliant Colours, Wisconsin, United States Of America

Rock Sculptures Dot The Shoreline As The Sun Dips Below The Horizon In Cave Point, Sturgeon Bay, Wisconsin, United States Of America

Sunrise At Cave Point In Sturgeon Bay, Wisconsin, United States Of America

Seeing Into The Clear Rocky Water At Sunset At Cave Point In Sturgeon Bay, Wisconsin, United States Of America

Caribbean, British Virgin Islands, Virgin Gorda, The Baths, The Crawl, Woman doing yoga in sea cave.