Movile Cave

[1] It is notable for its unique groundwater ecosystem abundant in hydrogen sulfide and carbon dioxide, but low in oxygen.

Life in the cave has been separated from the outside for the past 5.5 million years and it is based completely on chemosynthesis rather than photosynthesis.

[2][3] Movile Cave is a network of paths[dubious – discuss] in limestone that are approximately 200 metres (660 ft) long,[citation needed] with portions that are partially or fully submerged by hydrothermal waters.

[7] The cave is known to contain 57 animal species,[8][9] among them leeches, spiders, pseudoscorpions,[10] woodlice,[11] a centipede (Cryptops speleorex),[12] a water scorpion (Nepa anophthalma),[13] and also a snail.

[10][1][14] The cave is closed to the general public and only a few researchers are permitted inside each year, in order to minimize disturbance to the fragile ecosystem.