Leviathan Kenya

At 12km in total length, the aptly named Leviathan is one of the longest lava tubes in the world, and the longest in Africa. This type of cave is created by a cooling crust forming on a moving flow of lava – when molten rock has drained from the inside just the solidified shell remains. Try organising an expedition through Savage Wilderness. Otherwise, you’re only allowed to enter the cave in the company of a KWS ranger, with full caving equipment and with prior permission from the warden.