Only after World War II did the secret spill: Ōkunoshima, located in the Inland Sea of Japan between Hiroshima and Shikoku, was the top-secret site for manufacturing chemical warfare. When the factories were closed down, a number of exotic wild rabbits were seen freely roaming the island. They were assumed to have been the test subjects for the chemical weapons, which the military failed to eradicate when the factory was demolished.

Dancers dressed as futuristic characters perform during a show at The Robot Restaurant on June 29, 2014 in Tokyo, Japan. The now famous Robot Restaurant opened two years ago in Kabukicho area of Shinjuku at an estimated cost of 10 million U.S. dollars. Performances are held three times a day and cater mostly to foreign tourists. The cabaret style shows include bikini clad futuristic dancers, performers dressed as robots and a host of large scale robots and vehicles controlled with remotes by stage hands dressed as Ninjas. (Photo by Chris McGrath/Getty Images)

A bomb squad member wearing heavy equipment leaves the explosion site at the Yasukuni shrine precints in Tokyo, Japan, 23 November 2015. More than 100 police, firefighters and officials gathered at the site after an explosion was heard in the toilets of the Yasukuni Shrine, a controversial war shrine in the capital Tokyo. Local media reports said police found possible traces of an explosion, as well as batteries and wires at the shrine. There were no reports of injuries. (Photo by Franck Robichon/EPA)

A woman applies lipstick in a car that is parked at a beach facing a volcanic rock called Devil's Finger outside Yuzhno-Kurilsk, the main settlement on the Southern Kurile island of Kunashir September 15, 2015. Russian residents of the island chain at the centre of a dispute between Japan and Russia that has held up a treaty to formally end World War Two hope a diplomatic solution will lure tourists and investment to help refurbish rickety infrastructure. The Southern Kuriles are referred to in Japan as the Northern Territories. (Photo by Thomas Peter/Reuters)

A performer wearing a lion mask performs the Ise Daikagura lion dance at the remote village of Yamanawa on February 08, 2021 in Ryuo, Japan. Ise Daikagura is a group of traditional Lion Dance performers who pray in front of farmers houses and businesses for good grain harvests and disease-free lives. (Photo by Buddhika Weerasinghe/Getty Images)

Dog groomers participate in a contest at the “Interpets” international pet fair in Tokyo, Japan, 01 April 2021. (Photo by Franck Robichon/EPA/EFE)

Waka Tsukiyama and Sayaka Unagi compete during the Women's Pro-Wrestling “Stardom” at Korakuen Hall on September 06, 2021 in Tokyo, Japan. (Photo by Etsuo Hara/Getty Images)

A sommelier serves the glass with 2021 Beaujolais Nouveau wine of a young woman bathing in a red colored hot water bath, on the day of the Beaujolais Nouveau official release, at Hakone Kowakien Yunessun hot spring resort in Hakone, Japan, 18 November 2021. Japan is a major market for the Beaujolais Nouveau. However, the country's total Beaujolais Nouveau imports are expected to fall by 20 per cent from 2019 to around 3,6 million bottles, amid the ongoing coronavirus pandemic. (Photo by Franck Robichon/EPA/EFE)