Between 1929 and 1945, there was a major poison gas production facility located on Okunoshima Island in Japan. Over 6000 tons of mustard gas was produced on the island for use by the Japanese Army. While there is no longer a poison gas factory on the island, there is a poison gas museum, as well as something else out of the ordinary:
But now, Okunoshima Island is becoming better known as “Usagi Shima” (meaning Rabbit Island), a “bunny paradise” where robust leporids numbering in the hundreds roam freely and fearlessly. According to the Mainichi paper’s reportage, it’s believed that the rabbits were first introduced to the island in 1971 when an elementary school in Takehara dumped several of the animals there after being overwhelmed by the responsibilities required to keep rabbits at school. However, many other sources state that the rabbits of Usagi Shima island are direct descendants of lab animals (upon which the Imperial Army’s poisonous gases were tested) set loose by factory workers at the end of WWII.