Hashima Island (端島, or correctly Hashima, as -shima is Japanese for island), commonly called Gunkanjima or Gunkanshima (軍艦島; meaning Battleship Island), is one among 505 uninhabited islands in the Nagasaki Prefecture about 15 kilometers from Nagasaki itself. The island was populated from 1887 to 1974 as a coal mining facility. The island’s most notable features are the abandoned concrete buildings and the sea wall surrounding it. It has been administered as part of Nagasaki city since 2005; it had previously been administered by the former town of Takashima.
The island is increasingly gaining international attention not only as one of the modern international heritages in the region, but also for the housing complex remnants in the years from Taisho Era to Showa Era. Moreover, the island has become the frequent subject of a discussion among enthusiasts for ruins.
Since the abandoned island has not been maintained, several buildings have already collapsed. Other existing buildings are subject to breakage. In this regard, however, certain collapsed exterior walls have been restored with concrete. While the island was owned by Mitsubishi Material up until 2002, it was voluntarily transferred to Takashima town. Currently Nagasaki city, which absorbed Takashima town in 2005, exercises jurisdiction over the island. A small portion of the island was re-opened for tourism on April 22, 2009. A full reopening of the island would require an enormous amount of money to make the premises safe, due to the aging of the buildings.
Text from Wikipedia, Hashima Island