A muddied family photograph sits on a hallway stairwell in an apartment block on March 17, 2011 in Kensennuma, Japan. Residents were allowed back to their homes today and began the massive cleanup operation caused by a 9.0 magnitude strong earthquake that struck on March 11 off the coast of north-eastern Japan. The quake triggered a tsunami wave of up to 10 metres which engulfed large parts of north-eastern Japan. The death toll has risen past 5000 with at least 8600 people still missing. (Photo by Chris McGrath/Getty Images)

A dog takes a rest under a destroyed house at a site where a landslide swept through a residential area at Asaminami ward in Hiroshima, western Japan, August 20, 2014. At least 36 people, including several children, were killed in Japan on Wednesday, when landslides triggered by torrential rain slammed into the outskirts of the western city of Hiroshima, and the toll could rise further, police said. Seven people were missing after a month's worth of rain fell overnight, loosening slopes already saturated by heavy rain over the past few weeks. (Photo by Toru Hanai/Reuters)

Smithsonian National Zoo biologist Leigh Pitsko releases a male lion cub for its swim test in the zoo habitat moat, in Washington May 6, 2014. Four, unnamed ten-week old lion cubs were tested today for their ability to swim and remove themselves from their zoo habitat moat. (Photo by Gary Cameron/Reuters)

Four-year-old Chinese boy Huang Yang plays with five-year-old beluga whale Xiao Xin at the Qingdao Ocean World on November 3, 2007 in Qingdao of Shandong Province, China. Huang Yang began swimming as a baby and fell in love with the whale after watching its performance. On the International Children's Day, June 1 this year, the Qingdao Ocean World has made the boy's dream come true when they allowed Huang Yang to swim with the beluga whale. (Photo by China Photos/Getty Images)

Atsushi Abe and Yumi Adachi from Japan perform in the synchronised swimming mixed duet technical routine preliminary at the Aquatics World Championships in Kazan, Russia July 25, 2015. (Photo by Michael Dalder/Reuters)

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)