Aokigahara

Aokigahara, also known as the Sea of Trees , is a forest on the northwestern flank of Mount Fuji on the island of Honshu in Japan, thriving on 30 square kilometres (12 sq mi) of hardened lava laid down by the last major eruption of Mount Fuji in 864 CE. The western edge of Aokigahara, where there are several caves that fill with ice in winter, is a popular destination for tourists and school trips. Parts of Aokigahara are very dense, and the porous lava rock absorbs sound, contributing to a sense of solitude that some visitors attribute to the forest.