A cave is "a natural opening in the ground extending beyond the zone of light and large enough to permit the entry of man," according to the U.S. Geological Survey. Caves can range in size from single rooms to large formations with winding passageways that extend for miles. Caves typically form in types of rock, such as limestone, that dissolve in water. It can take tens of thousands to hundreds of thousands of years for caves to form. The study of caves is called speleology, and the exploration of caves is called spelunking. Caves are famous of their dripstone features called speleothems, the most well-known of which are stalactites and stalagmites. Many of the strange creatures found in caves have adapted to live in near or total darkness — some are blind to visible light. See cave pictures and read about the latest cave discoveries and speleological research below.
There were no lions in 16th-century Puerto Rico — so was the cave drawing made by someone who'd actually seen one?
Ancient caves mark the beginning of recorded burial rituals, but there's still so much we don't know about the history of human graves.
Archaeological discoveries throughout the Americas are pushing back the date for when humans reached the New World by thousands of years, rewriting the long-standing theory that people arrived only 13,000 years ago.
Researchers think the morbid practice originated with pagan people who settled in the region after the Romans drove out the Jews.
The discovery of a skull and shin bone fragment in a cave in Laos pushes back the earliest known date of Homo sapiens in Southeast Asia.
These "greedy" eels likely retreated into the gloomy depths of underwater caves in search of tasty crustaceans and are adapting to the darkness by going blind, one eye at a time.
Stone Age dots, lines and Y-shaped marks might represent a type of proto-writing created by hunter-gatherers who lived in Europe at least 20,000 years ago.
Construction workers in Israel unexpectedly broke into a 3,300-year-old cave that looks like an "Indiana Jones film set."
The Neanderthals and Denisovans — both relatives of modern humans — were roommates, literally, for thousands of years in a remote Siberian cave, two new studies find.
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