Japan Self-Defense Force (JSDF) soldiers and firefighters make rescue works among mountain lodges, covered with volcanic ash near the peak of Mt. Ontake, which straddles Nagano and Gifu prefectures in this September 28, 2014 photo taken and released by Kyodo. More than 30 people were feared dead on Sunday near the peak of the Japanese volcano that erupted a day earlier, sending a huge cloud of ash and rock tumbling down its slopes, while packed with hikers. (Photo by Reuters/Kyodo News)

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.

Dancers dressed as futuristic characters perform during a show at The Robot Restaurant on June 29, 2014 in Tokyo, Japan. The now famous Robot Restaurant opened two years ago in Kabukicho area of Shinjuku at an estimated cost of 10 million U.S. dollars. Performances are held three times a day and cater mostly to foreign tourists. The cabaret style shows include bikini clad futuristic dancers, performers dressed as robots and a host of large scale robots and vehicles controlled with remotes by stage hands dressed as Ninjas. (Photo by Chris McGrath/Getty Images)

Japan Self-Defense Force members pay their respect to unidentified earthquake victims in vehicles during a mess funeral on April 8, 2011 in Yamamoto, Miyagi Prefecture, Japan. The 9.0 magnitude strong earthquake struck offshore on March 11 at 2:46pm local time, triggering a tsunami wave of up to ten metres which engulfed large parts of north-eastern Japan, and also damaging the Fukushima nuclear plant and threatening a nuclear catastrophe. The death toll continues to rise with numbers of dead and missing exceeding 20,000 in a tragedy not seen since World War II in Japan. (Photo by Athit Perawongmetha/Getty Images)

A woman looks at photographs of dogs to choose a pet to rent at Puppy The World on January 24, 2009 in Tokyo, Japan. Rent-a-dog is becoming increasingly popular amongst people who love dogs but are unable to look after a pet full time due to limited living space or long working hours. Customers pay the dog-rental outlet around 2500 yen (32.5 USD) for an hour, and usually take their rented pet for a walk along the nearby beach. (Photo by Junko Kimura/Getty Images)

Carrying a portable shrine on their shoulders, participants all clad in traditional happi coats, parade through precincts of the Kanda Myojin shrine during the annual summer festival in Tokyo, Saturday, May 9, 2015. (Photo by Eugene Hoshiko/AP Photo)

Women in yukatas, or casual summer kimonos, take their selfie in front of paper lanterns during the annual Mitama Festival at the Yasukuni Shrine, where more than 2.4 million war dead are enshrined, in Tokyo, Japan July 13, 2017. (Photo by Kim Kyung-Hoon/Reuters)