A man rides his loaded tricycle next to three schoolgirls in Shanghai on December 11, 2015. (Photo by Johannes Eisele/AFP Photo)

This photo taken on April 4, 2021 shows migratory birds flying over a wetland near the Yalu River in Dandong, in China's northeastern Liaoning province. (Photo by AFP Photo/China Stringer Network)

Recording artists Demi Lovato (L) and Iggy Azalea perform on the Pepsi Stage, during the 2015 MTV Video Music Awards, at The Orpheum Theatre on August 30, 2015 in Los Angeles, California. (Photo by Frederick M. Brown/Getty Images for MTV)

In this Thursday, May 16, 2013 file photo, Finland's Krista Siegfrids, second right, kisses a dancer as she performs her song “Marry Me” during the second semifinal of the Eurovision Song Contest at the Malmo Arena in Malmo, Sweden. That was the first girl-on-girl kiss in the history of the annual competition. Previously, organizers had sought to prevent similar embraces citing the competition's status as a family event. (Photo by Alastair Grant/AP Photo)

TCU Horned Frogs twirler performs at halftime of the game against the Baylor Bears at Amon G. Carter Stadium in Fort Worth, Texas, USA on November 6, 2021. (Photo by Kevin Jairaj/USA TODAY Sports)

British singer-songwriter Raye (L) during The BRIT Awards 2021 at The O2 Arena on May 11, 2021 in London, England. (Photo by JMEnternational/JMEnternational for Brit Awards/Getty Images)

A racegoer uses the camera on her phone to check her hair on the opening day of the Grand National Festival at Aintree Racecourse on April 3, 2014 in Aintree, England. The three days of racing attracts thousands of racegoers and fans from across the world. The meeting culminates with millions of pounds being wagered on the runners taking part in Europe's richest jump race, the Grand National. (Photo by Christopher Furlong/Getty Images)

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.