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.

Zurab Gurielidze, a director of the Tbilisi Zoo, speaks to the media while standing next to a hippopotamus named Begi at the zoo in Tbilisi, Georgia, September 13, 2015. Tbilisi zoo, which was partly destroyed and some 300 animals escaped or died in the floods that also killed at least 19 people in June, was reopened on Sunday. (Photo by David Mdzinarishvili/Reuters)

A Ukrainian woman begs Ukrainian President Petro Poroshenko to stop the bombing in Donetsk after shell hit the residential area where she lives, killing two civilians in Donetsk's Kyibishevsky district, on January 29, 2015. (Photo by Manu Brabo/AFP Photo)

A man wearing a costume of the StarWars protagonist Din Djarin poses in front of a giant replica of the Razor Crest, a gunship from the StarWars spinoff series “The Mandalorian” used by the hit TV show's mysterious bounty hunter to roam the galaxy's outer reaches, in a park of the eastern Siberian city of Yakutsk on March 14, 2021. (Photo by Evgeniy Sofroneyev/AFP Photo)

A dragon crew team performs at a shopping mall to welcome the Lunar new year in Taoyuan, Taiwan on February 1, 2022. (Photo by Ann Wang/Reuters)

The digital art piece “Visor” by Mad Dog Jones is pictured ahead of an auction at Sotheby’s in London, United Kingdom on June 1, 2021. (Photo by Mad Dog Jones/Reuters)

Relatives of Ukrainian photographer Maksim Levin, killed while covering Russia's attack on Ukraine, react during his funeral in the town of Boiarka, outside of Kyiv, Ukraine on April 4, 2022. (Photo by Valentyn Ogirenko/Reuters)

Participants of the Cologne Pride rally pose in front of the Cathedral in Cologne, Germany, Sunday, July 3, 2022. This year's Christopher Street Day (CSD) Gay Parade with thousands of demonstrators for LGBTQ rights is the first after the coronavirus pandemic to be followed by hundreds of thousands of spectators in the streets of Cologne. (Photo by Martin Meissner/AP Photo)