A dog walks on the street as it snows in Kyoto on January 25, 2024. (Photo by Philip Fong/AFP Photo)

People are walking with umbrellas on a snow-covered street during the first snowfall of the year in Tokyo, Japan, on February 5, 2024. (Photo by Jerome Gilles/NurPhoto/Rex Features/Shutterstock)

A participant marches during the Tokyo Rainbow Pride parade, celebrating advances in LGBTQ+ rights and calling for marriage equality, in Tokyo, Japan on April 21, 2024. (Photo by Issei Kato/Reuters)

A performer dressed as a zombie performs inside a “Zombie Shinkansen” bullet train bound for Osaka from Tokyo, inspired by the South Korean movie “Train to Busan” ahead of the Halloween season, Japan, on October 19, 2024. (Photo by Kim Kyung-Hoon/Reuters)

A tourist cools off in front of a misting fan near a venue of the Hozuki-Ichi (Japanese lantern plant fair), at Sensoji temple, in Tokyo, Japan, on July 10, 2025. (Photo by Kim Kyung-Hoon/Reuters)

Participants carry a portable shrine, or mikoshi, into the sea during a purification rite at the annual Kurihama Sumiyoshi Shrine Festival at Kurihama, Yokosuka city, south of Tokyo Sunday, July 27, 2025. (Photo by Eugene Hoshiko/AP 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.