Two sheep fight in a competition in Zhangjiakou, Hebei province, China on August 1, 2017. (Photo by Reuters/China Stringer Network)

A robot named “Robovie-II”, developed by Japanese robotics research institution ATR, moves around at a grocery store during a shopping assisting experiment by utilizing the robot in an ubiquitous network technology platform in Kyoto, western Japan January 6, 2010. (Photo by Yuriko Nakao/Reuters)

A couple watches office and residential buildings from the observation deck of Tokyo Skytree, the world's tallest broadcasting tower, in Tokyo, Japan, August 18, 2021. (Photo by Marko Djurica/Reuters)

Dogs and their owners wearing all types of colorful costumes participate in the Elizabeth Street Garden Halloween Pet Parade on November 4, 2023 in New York City. The parade was posponed from October dur to bad weather. (Photo by Andrew Schwartz/Splash News and Pictures)

Instructor Raquel Potí leads a stilt walking workshop at the Museum of Modern Art in Rio de Janeiro, Brazil, Saturday, January 27, 2024. Potí is chiefly responsible for the explosion of stilt walking in Rio, having trained more than 1,000 kids and adults over the past decade. (Photo by Silvia Izquierdo/AP Photo)

This hazel dormouse is being given a once-over by a disease risk team at ZSL London Zoo, UK in May 2025, as part of reintroduction programme. (Photo by David Levene/The Guardian)

Tourists look at other festival-goers playing in the mud during the Boryeong Mud Festival at Daecheon beach in Boryeong, about 190 km (118 miles) southwest of Seoul, July 19, 2013. About 2 to 3 million domestic and international tourists visit the beach during the annual mud festival, according to the festival organisers. (Photo by Lee Jae-Won/Reuters)

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.