Aokigahara, often called the Sea of Trees, is a dense forest on old lava flows northwest of Mount Fuji. The ground is uneven and porous, with volcanic caves, mossy roots, and a quiet that feels very different from the open lake views nearby.
Visitors usually stick to marked trails or combine the forest with the nearby lava caves. Do not wander off-path: the forest is easy to get turned around in, and parts of it have a sombre reputation.