Colossal Cavern

Colossal Cavern is a cave in Kentucky, USA, the main entrance of which is at the foot of a steep hill beyond Eaton Valley, and 14 miles from Mammoth Cave. It is connected with what has long been known as the Bed Quilt Cave. Several entrances found by local explorers were rough and difficult. They were closed when the property was bought in 1896 by the Louisville & Nashville railway and a new approach made. From the surface to the floor is 240 ft. under Chester Sandstone and in the St Louis Limestone.

Fossil corals fix the geological age of the rock. The temperature is uniformly 54 F, and the atmosphere is optically and chemically pure. Lovely incrustations alternate with queer and grotesque figures. There are exquisite gypsum rosettes and intricately involved helictites.

Bedquilt, not Colossal, was also the inspiration and setting for the first truly interactive computer game. Co-written by Will Crowther, a caver who spent many hours helping to survey the cave and appropriately called "Colossal Cave", the computer game became the inspiration for the classic game Adventure.