Servicewomen march in formation during a Victory Day military parade marking the 74th anniversary of the victory over Nazi Germany in the 1941-1945 Great Patriotic War, the Eastern Front of World War II, in Moscow's Red Square, Russia on May 9, 2019. (Photo by Valery Sharifulin/TASS)

With her husband, Brazil's new President Jair Bolsonaro in the background, Brazil's new first lady Michelle Bolsonaro gives a military salute from the Planalto Presidential palace, in Brasilia, Brazil, Tuesday, January 1, 2019. (Photo by Silvia Izquierdo/AP Photo)

A billboard depicting a soldier, with a slogan reading “Contract service. A real man's job”, in St. Petersburg, Russia, 02 June 2023. On 24 February 2022, Russian troops entered Ukrainian territory in what the Russian president declared a “Special Military Operation”, starting an armed conflict. (Photo by Anatoly Maltsev/EPA)

Chelsea pensioner Mike Smith in the rear of one of two Spitfires flying over Sussex during a surprise flight organised by the Taxi Charity for Military Veterans on Tuesday, September 12, 2023. (Photo by Gareth Fuller/PA Images via Getty Images)

A supporter of presidential candidate and former chairman of the NATO Military Committee and Czech Army General Petr Pavel hands out leaflets, ahead of a direct presidential election that will start on January 13, in Prague, Czech Republic on January 5, 2023. (Photo by David W. Cerny/Reuters)

A Palestinian boy, who was displaced by Israel's military offensive with his family on south Gaza, holds a cat as he attempts to return to his home in north Gaza through an Israeli checkpoint, in the central Gaza Strip, on April 15, 2024. (Photo by Ramadan Abed/Reuters)

“Only the most intrepid urban explorers cross the tattered ruins of the old Iron Curtain to endure the excessive bureaucracy, military paranoia and freezing winds of the East to hunt for the ghosts of an empire. Rebecca Litchfield is one who couldn't resist the haunting allure of the ruins of the Soviet Union”. – Yahoo News. Photo: Hungary, MAV 424 Steam Train. (Photo by Rebecca Bathory)

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.