A mother of a victim who was onboard sunken ferry Sewol, leaves a message on a desk used by her child at an empty classroom, which was preserved since the disaster, at Danwon high school during the second anniversary of the disaster in Ansan, South Korea, April 16, 2016. (Photo by Kim Hong-Ji/Reuters)

A woman surveys the damage after the earthquake on March 17, 2011 in Kensennuma, Japan. (Photo by Chris McGrath/Getty Images)

A cat wears a “Tsunagaru Col” gadget next to a smart phone displaying the connected app, at the Anicall Corp booth during the Wearable Device Technology Expo in Tokyo January 14, 2015. The gadget (“Tsunagaru” means connection) for animals tracks information about pets, such as the location and other animals the pet might be interacting with, with the purpose of providing “social networking” for animals. The expo runs until January 16 as a part of Japan's largest electronic exhibition expected to attract around 77,000 visitors, according to organisers. (Photo by Yuya Shino/Reuters)

Sete Tamang, 20, avalanche survivor, waits to receive the bodies of his colleagues outside a morgue at Teaching Hospital in Katmandu, Nepal, Monday, October 20, 2014. Nepal was wrapping up rescue operations in its northern mountains Monday, saying all the hikers believed to have been stranded on a trekking route by a series of deadly blizzards are now safe. (Photo by Niranjan Shrestha/AP Photo)

Firefighters use flashlights to search for survivors among the rubble of collapsed buildings after a landslide hit an industrial park in Shenzhen, Guangdong province, China December 20, 2015. (Photo by Tyrone Siu/Reuters)

A guard stands at Dityatki checkpoint, marking a 30 km (18-mile) zone around the Chernobyl nuclear power plant April 23, 2013. Ukraine will mark the 27th anniversary of the Chernobyl disaster, the world's worst civil nuclear accident, on April 26. (Photo by Gleb Garanich/Reuters)

Photo taken on November 5, 2015 shows flood in Bento Rodrigues, a town in the southeastern Brazilian state of Minas Gerais, after a dam at a mining waste site burst early Thursday. An iron ore tailings dam in the southeast Brazilian state of Minas Gerais collapsed Thursday, killing at least 15 people, according to local media reports. (Photo by Agencia Estado/Xinhua Press/Corbis)