Hashima Island aka Battleship Island. Former coal mining facility owned by Mitsubishi Motors, it was once the most densely populated place on earth, packing over 13K people into each square kilometre. Operated from 1887 until 1974, after which the coal industry fell into decline. With their jobs gone and no other reason to stay in this mini urban nightmare, almost overnight the entire population fled back to the mainland, leaving most of their stuff behind to rot.
端島(軍艦島), Hashima Island, Gunkan-jima (Battleship Island), Japan, fifteen kilometers away from the infamous Nagasaki. This is amazing inspiration for a short story and I can't wait to incorporate it into one.
It is known for its coal mines and their operation during the industrialization of Japan. Mitsubishi bought the island in 1890 and began the project, the aim of which was retrieving coal from undersea mines.
Hashima Island, Japan | Hashima used to be a coal producing island and at one time had the highest population density in the world. There are a number of documentaries on it. Nature is now reclaiming it amazingly quickly!