Ōkunoshima is an old  island, which for many years was absent on official maps of the country, and few knew of its existence. This small island is located in the Inland Sea of Japan in the city of Takehara, Hiroshima Prefecture.

So before the Second World War ÅŒkunoshima used to be a top-secret military site manufacturing poison gas for chemical warfare. They used mustard gas which was formally rejected by Japan Government, according to the signed the Geneva Protocol of 1925. Rabbits were just those on whom experiments were conducted. At the end of the Second World War, the base was closed and the rabbits released. Now, this island is inhabited by a few hundred rabbits, a museum and even the opened hotel.

Source: Flickr