The Aokigahara (or Sea of Trees) is a 35 km² forest based in the north east of Mount Fuji, in Japan. Many tales are told about this place, since it's one of the quietest places in the world because of the trees that block the wind and of the absence of wildlife.
So, it's known as a place of demons and Yūrei - the ghosts of those who died in a quick, or violent manner and were unable to pass into the afterlife because the proper rites were not performed (well known in the Japanese folklore, mythology) because it's the second place in the world with more suicides (the first one is the Golden Gate Bridge in San Francisco) - Every year a hundred bodies are discovered there, and some have been there for a while. So, why is that happening?

In the first place, that space gained popularity because of a Novel book by Seicho Matsumoto - Nami no Tō, a history that ends with a couple committing suicide in the forest. On the other hand, since the nineteenth century people did Ubasute there - a Japanese tradition consisting in taking the old ones and people with diseases to a forest or a peak of a mountain, letting them die there, starving or with cold.