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.

Masked revellers pose in St. Mark's Square during the Venice Carnival, February 7, 2015. The Venetian carnival started on January 31 and runs until February 17, forty days before Easter celebrations. (Photo by Stefano Rellandini/Reuters)

in Qayyarah, about 31 miles (50 km) south of Mosul, Iraq, Sunday, October 23, 2016.in Qayyarah, some 50 kilometers south of Mosul, Iraq, Sunday, Oct. 23, 2016. Islamic State fighters torched a sulfur plant south of Mosul, sending a cloud of toxic fumes into the air that mingled with oil wells the militants had lit on fire to create a smoke screen. (Photo by Marko Drobnjakovic/AP Photo)

A visitor celebrates after attending a bare hand fishing event in a frozen river during the Hwacheon Sancheoneo Ice Festival at Hwacheon-gun, Gangwon province, South Korea, 09 January 2016. The festival runs under the theme “Unfrozen Hearts, Unforgettable Memories” from 09 January to 31 January 2016. (Photo by Jeon Heon-Kyun/EPA)

A reveler and a child street vendor pose for a photo during the Banda de Ipanema Carnival parade in Rio de Janeiro, Brazil, Saturday, January 31, 2015. Rio's over-the-top Carnival is the highlight of the year for many local residents. Hundreds of thousands of merrymakers are beginning to take to the streets in open-air “blocos” parties. (Photo by Silvia Izquierdo/AP Photo)

Devotees offer prayer by rolling on the street during the final day of the month-long Swasthani festival of Bhaktapur, near Kathmandu, February 3, 2015. During the festival, devotees recite one chapter of a Hindu tale daily from the 31-chapter sacred Swasthani Brata Katha book, that is dedicated to God Madhavnarayan and Goddess Swasthani, alongside various other gods and goddesses and the miraculous feats performed by them. The devotees also go on pilgrimages to various temples, perform religious rituals, take a holy bath in the rivers and fast for a month, especially among women who believe fasting helps in their family's well-being or in getting them a good husband. (Photo by Navesh Chitrakar/Reuters)

A person wearing a mask of Elmo walks around Times Square during the pass of the snowstorm on January 31, 2021 in New York City. New York City Mayor Bill de Blasio declared a state of emergency order due to the arriving storm that's expected to wallop New York, where airports are expected to cancel the majority if their flights. (Photo by Eduardo Munoz Alvarez/VIEWpress)

A woman cries as she watches a building burn after a protest over the death of George Floyd, Sunday, May 31, 2020, in La Mesa, Calif. Protests were held in U.S. cities over the death of Floyd, a black man who died after being restrained by Minneapolis police officers on May 25. (Photo by Gregory Bull/AP Photo)