The world is full of amazing places. Though most people travel to see such sites above the earth’s surface, many are actually beneath it. Caves contain their own ecosystems that would not be sustainable above ground, and their environments are often studied by scientists known as speleologists.

Often hidden in jungles or wild rocky regions, they may not always be easily accessible, but that makes them all the more alluring to experience. Those who venture beyond the cave mouths – serious cave explorers are known as spelunkers, from the Latin word for cave, “spelunca”) often encounter narrow passages, precipitous drops, waterfalls and pools, and other potential hazards along the way, but that just adds to their appeal for many. (These are the most mysterious places in the world.)

While caves may be foreboding to some, many are things of great beauty. To determine the most beautiful caves in the world, 24/7 Tempo consulted numerous websites including Timeout and The Active Times, focusing on caves of striking natural beauty, as well as a few with exceptional man-made elements.

Click here to see the most beautiful caves in the world

The caves on the list vary significantly in age, from several thousand to several million years. Some are made of rock, others of ice. They may be surprisingly colorful or majestic in their solemnity. Each, though, is stunning in its own way. (These are the most colorful natural wonders in the world.)