A woman looks at a swimmer getting herself warm after the annual Christmas winter swimming competition in the Vltava river in Prague December 26, 2014. (Photo by David W. Cerny/Reuters)

Cole Yeoman steps over a large crack along River Road, Avonside on February 25, 2011 in Christchurch, New Zealand. The death toll has risen to 113 and the hope for finding survivors is fading as rescuers search through debris for over 200 still missing following a 6.3 magnitude earthquake that struck Christchurch on Tuesday. The quake, which was an aftershock of a 7.1 magnitude quake that struck the South Island city on September 4, 2010, has seen damage and fatalities far exceeding those of the original. (Photo by Martin Hunter/Getty Images). CHRISTCHURCH, NEW ZEALAND – FEBRUARY 25

A sculpture is displayed at the Olympic Sculptures Exhibition at the Sculpture Park September 4, 2006 in Changchun of Jilin Province, China. (Photo by China Photos/Getty Images)

“Zeybeks”. That's Dance, Sunward and Zeybeks. (Photo by Hasan Baglar/2014 Sony World Photography Awards)

As the sun rises, Gentoo penguins start their day on Wednesday, February 17, 2016, on Sea Lion Island, Falkland Islands. Sea Lion Island, which lies about 10 miles to the south of mainland East Falkland, is the southern most human-inhabited island of the more than 750 islands and islets of the Falkland Islands. (Photo by Jahi Chikwendiu/The Washington Post)

A Shiite fighter from the Hashed al-Shaabi (Popular Mobilisation) patrols in the village of Ayn Nasir, south of Mosul, on October 29, 2016, after recapturing it from Islamic State group jihadists in an ongoing operation to retake the city of Mosul. Iraqi paramilitary forces launched an operation to cut the Islamic State group's supply lines between its Mosul bastion and neighbouring Syria, opening a new front in the nearly two-week-old offensive. (Photo by Ahmad Al-Rubaye/AFP Photo)

Skeletons are arranged in a bar scene as part of a competition to create Day of the Dead altars on pedestrian Regina Street in central Mexico City, Tuesday, November 1, 2016. The holiday honors the dead as friends and families gather in cemeteries to decorate their loved ones' graves and hold vigil through the night on Nov. 1 and 2. (Photo by Rebecca Blackwell/AP Photo)

A boat is stranded on Poyang Lake in Lushan City, China during low-water season on November 3, 2016. (Photo by Xinhua/Barcroft Images)