A woman plays around as she walks across a glass-bottomed suspension bridge in a scenic zone in Pingjiang county in southern China's Hunan province Thursday, September 24, 2015. The bridge, 300 meters (984 feet) long and 180 meters (590 feet), opened to visitors on Thursday for the first time since its conversion from a regular suspension bridge was completed. (Photo by Chinatopix Via AP Photo)

A Pakistani monkey handler Naseer Khan plays flute to attract passers by for a monkey show to earn his living in Islamabad, Pakistan, Monday, September 7, 2015. (Photo by B. K. Bangash/AP Photo)

Participants prepare backstage before the 5th “Strongo Cup” open amateur bodybuilding tournament at the State Opera and Ballet Theatre in Russia's Siberian city of Krasnoyarsk, November 1, 2014. Participants from all over Russia took part in the tournament competing in bodybuilding, body fitness and bikini fitness disciplines. (Photo by Ilya Naymushin/Reuters)

Women demonstrate on International Women's Day as they strike to demand the end to domestic violence and the country's prevailing “macho” culture, in Milan, Italy on March 8, 2023. (Photo by Claudia Greco/Reuters)

Italian actress Sophia Loren and US actor Marlon Brando at a cinema in Rome on November 11, 1954, where Brando received the Francesco Pasinetti Prize for his performance in the film “On The Waterfront”. (Photo by Keystone/Getty Images)

Female police officers from Istanbul's Motorcycled Police Unit wait to search vehicles during a roadside checkpoint operation on March 7, 2017 in Istanbul, Turkey. The rapid response unit nicknamed Dolphins is used primarily in crime prevention operations and has 25 female officers. 6% of Turkey's 250,000 strong police force are women, March 8 marks International Women's Day. (Photo by Chris McGrath/Getty Images)

A mechanical horse-dragon made of wood and steel is presented to the public in Nantes, western France on August 26, 2014. This horse-dragon, created by the French artist Francois Delaroziere of “Les Machines de l'île” (The Machines of the Isle), is the hero of the show "Long Ma" which will be presented in Beijing on October 17, 2014 as part of the fiftieth anniversary of the relationship between France and China. (Photo by Jean-Sebastien Evrard/AFP Photo)

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.