There is a cave in the world which has its own ecosystem. This cave has a forest, river, rocks, trenches and much more. It was declared the world's largest cave in 2009.

Scientists have found ancient nail tooth shark fossils deep inside Mammoth Cave in Kentucky, revealing new information about ...

Thick stands of stalagmites rise from moon-pale banks of sediment in the Drunken Forest ... some as big as my hand. An expedition team member climbing toward the roof of Deer Cave dangles ...