Sign up for free

Newsletters

Once a month
get new photos
and expert tips.

Science and Space
Main Health and Human Body Earth Space Prehistoric World A-Z

Karst Cave, China

Photo: China's Reed Flute Cave in blue light

Looking like the set of a science fiction movie, China's Reed Flute Cave is bathed in purple-blue light. Created by an underground river more than a half million years ago, this highly accessible karst formation is one of the region's most popular tourist attractions. But during World War II the cave served a different purpose—it doubled as an air raid shelter.

Photograph by Raymond Gehman