The Japanese island Gunkanjima resembles a fortress. Many people also call it the Battleship Island, because it also resembles a very large ship. The entire island is surrounded by walls. The buildings were built extremely close to each other, which is something that amplifies the island’s reputation of a ghost town. This coal mining island is located just off the coast of Nagasaki and it has been inhabitated for over forty years. Almost six thousand people lived there in the 50s, which gave it the highest population density in the world. However, at some point the coal ran out. The mines were closed down and the inhabitants abandoned the island.