In Nagasaki Prefecture, there is an artificially created, uninhabited island known as Gunkanjima (Battleship Island).
There were once 5,000 people living on the island in a town famous for having the highest population density in the world, but the decline of the coal mining industry led to accelerating depopulation, and it has been uninhabited for over 40 years.
Take a look at this island, which has retained the forms of its gigantic buildings even as it has decayed and undergone a transformation.
It is currently only possible to visit a path of around 300 meters that has been checked for safety.
You can join for ￥3,600, so book here if you are interested.