Hashima in Nagasaki prefecture, known also as Gunkanjima or 'Battleship Island', has been inscribed on UNESCO's list of World Heritage sites.
It was established as an undersea coal mine in 1887, and operated until 1974, with a peak population of over 5,000 living on the island. After the mine's closure, the island was abandoned and the buildings fell into disrepair, but it has since become a tourist attraction.
Movie fans may recognise it as the inspiration for the lair of James Bond's adversary Raoul Silva in Skyfall; while exterior shots were used, no footage was shot on the island, likely owing to safety concerns.
I uploaded a few photos on Wiki but I prefer those two: https://commons.wikimedia.org/wiki/Category:Hashima_(Nagasaki)#/media/File:Block_65_on_Hashima_Island.jpg and https://commons.wikimedia.org/wiki/File:Gunkanjima_Island.jpg. Feel free to use them :)