British model Leomie Anderson and British television presenter AJ Odudu pose as they arrive for the Brit Awards at the O2 Arena in London, Britain on February 11, 2023. (Photo by Maja Smiejkowska/Reuters)

British television, radio presenter and DJ Maya Jama arrives at The BRIT Awards 2022 at The O2 Arena on February 8, 2022 in London, England. (Photo by David M. Benett/Dave Benett/Getty Images)

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)

Star of Cabaret, English actor Eddie Redmayne attends The Olivier Awards 2022 with MasterCard at the Royal Albert Hall on April 10, 2022 in London, England. (Photo by David Levene/The Guardian)

An Extinction Rebellion protestor holds up a sign saying “You Can Change Climate Change” in St Martin's Lane in London, United Kingdom on August 23, 2021. (Photo by James Veysey/Rex Features/Shutterstock)

People view pelicans napping on a footpath in St James’s Park in London, United Kingdom on a mild day October 18, 2021. (Photo by Stephen Chung/Alamy Live News)

English actress Michelle Keegan at “The Jonathan Ross Show” TV show, Series 18, Episode 7 in London, United Kingdom on December 4, 2021. (Photo by Brian J. Ritchie/Hotsauce/Rex Features/Shutterstock)

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.