No one fully understands the cave’s ventilation system, but this particular entrance “exhales ... A lot of science can be gathered underground, much of it contained in speleothems—mineral ...

A sinkhole opened up on a Midwest dairy farm in 1940 to reveal an underground river, a 21-mile cave system and rare creatures ...

Deep beneath Namibia lies something extraordinary - the world's largest non-subglacial underground lake, known as Dragon's ...