The Chernobyl disaster was a catastrophic nuclear accident that occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in Ukraine, which was under the direct jurisdiction of the central authorities of the Soviet Union. The Chernobyl disaster is the worst nuclear power plant accident in history in terms of cost and resulting deaths, and is one of only two classified as a level 7 event (the maximum classification) on the International Nuclear Event Scale (the other being the Fukushima Daiichi nuclear disaster in 2011). Photo: Graffiti of a crying baby on a wall, Chernobyl Power Plant, Chernobyl, Ukraine. (Photo by Hans Neleman/Getty Images)

Riot police walk in the street as a couple kiss on June 15, 2011 in Vancouver, Canada. Vancouver broke out in riots after their hockey team the Vancouver Canucks lost in Game Seven of the Stanley Cup Finals. (Photo by Rich Lam/Getty Images)

A supporter of BJP dances during celebrations after learning of initial poll results outside the party headquarters in New Delhi, on May 16, 2014. (Photo by Anindito Mukherjee/Reuters)

Damir Sagolj has won Reuters photojournalist of the year for his 2016 work, which included documenting the deadly Philippine drug war and the North Korea congress. Here: A 17 year old girl lays dead next to her doll after she and her friend were killed by unknown motorcycle-riding gunmen, in an alley in Manila, Philippines early October 26, 2016. According to the police, a sign on a cardboard reading “Tulak ka, hayop ka”, which translates to “You are a (drug) pusher, you are an animal” was found with the body of girl's friend. (Photo by Damir Sagolj/Reuters)

Myanmar punks walk in the downtown area as they take part in a punk gathering ahead of the Thingyan water festival in Yangon, Myanmar, 12 April 2017. Myanmar punks have been gathering in Yangon on the day ahead of Thingyan water festival to celebrate every year. The annual water festival is marked with large groups of people congregating to celebrate by splashing water and throwing powder at each others faces as a symbolic sign of cleansing and washing away the sins from the old year to mark the traditional New Year in countries such as Myanmar, Thailand, Laos and Cambodia. This year, the Myanmar Thingyan water festival falls on 13 April and ends on 16 April. (Photo by Lynn Bo Bo/EPA)

Army soldiers prepare a military elephant for the parade during a rehearsal for Sri Lanka's 68th Independence day celebrations in Colombo, February 2, 2016. (Photo by Dinuka Liyanawatte/Reuters)

Participants stretch their bodies as they pose for pictures before the Beijing International Marathon in Beijing, China, September 20, 2015. About 30,000 runners participated in the annual running event. (Photo by Kim Kyung-Hoon/Reuters)

A Thai man climbs down from his home in a disused airplane on September 12, 2015 in Bangkok, Thailand. 3 impoverished Thai families have begun living in disused airplanes on a private field. The families, who collect and recycle garbage earning a few dollars a day, can't afford to rent and prefer to stay in the planes. (Photo by Taylor Weidman/Getty Images)