Caves are incredible underground worlds. Many people are interested in them.
What makes a cave? Near the coast, ocean waves hit cliffs and make holes. In the mountains, the moving ice in a glacier makes caves in the rock.
The most incredible caves are in soft rock called limestone. Rain falls on the limestone and makes holes. Slowly, the holes grow bigger and make caves. This takes thousands and thousands of years.
The Sarawak Chamber in Borneo is the biggest cave in the world. It’s longer than ten big planes!
Caves are usually very wet because water comes through the rock. Slowly, the raindrops mix with minerals and build incredible rock sculptures, called stalactites and stalagmites.
Thousands of years ago, people lived in caves. They didn’t have books or paper, so they drew pictures on the cave walls. People drew this picture in a cave in France, about 16,000 years ago.