Fugaku Wind Cave, 201 meters long with an average height of 8.7 meters, is found in the Aokigahara area. It is so named from Fugaku (富岳), a literary name for Mt. Fuji (富士山), and Fūketsu (風穴) for wind cave, because there is enough circulation of air on the cave. The walls of the cave are mostly made of basalt.