This island is one of hundreds of unpopulated islands around the Nagasaki area, and is known as Battleship Island due to its high sea walls. In 1890 the Mitsubishi company bought the whole island to mine coal from the bottom of the sea, causing much attention.
In 1916 massive concrete towers were built on the island to accommodate workers and by 1959 the population bloated to become one of the highest population densities in the world. In 1974 the mine closed as the market declined and today it is eerily empty with travel prohibited, but if it looks familiar it was the setting for 'Battle Royale II' in 2003.