Friends of Li Guojun drive a homemade tank-shaped vehicle in Kangping county, China. Li, a farmer who is a fan of tanks, spent six months with help from his friends to construct the almost 20-foot vehicle which weighs 2.5 tons. (Photo by Sheng Li/Reuters)

In this handout image provided by the Police of Swiss canton Valais the wreckage of a bus is seen after it crashed inside a motorway tunnel on March 13, 2012 in Sierre, Switzerland. 28 people, including 22 children, returning from a skiing holiday died in this bus accident. (Photo by Police Cantonale Valaisanne via Getty Images)

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)

An East German civilian (L) shows an East German customs officer the contents of his Trabant (auto) at checkpoint Potsdamer Platz in East Berlin in this November 24, 1989 file picture, as East Germany enforcing stringent customs controls to avoid smuggling. (Photo by Reuters)

Models present makeup creations during a show by Maybelline New York at the Berlin Fashion Week Autumn/Winter 2016 in Berlin, Germany, January 18, 2016. (Photo by Fabrizio Bensch/Reuters)

People in an illuminated cycle rickshaw look at a light installation at the Old Royal Library during the opening day of the "Festival of Light" show in Berlin, Germany, October 9, 2015. (Photo by Hannibal Hanschke/Reuters)

A woman holding an umbrella walks past the sculpture by Chinese artist Yue Minjun beside a road during a snow in Beijing, China, November 22, 2015. (Photo by Jason Lee/Reuters)

An Afghan policeman stands guard as smoke and flames rise from the site of a huge blast struck near the entrance of Kabul's international airport, in Kabul on August 10, 2015. A huge blast struck near the entrance of Kabul's international airport on August 10 during the peak lunchtime period, officials said, warning that heavy casualties were expected. “The explosion occurred at the first check point of Kabul airport”, said deputy Kabul police chief Sayed Gul Agha Rouhani. (Photo by Shah Marai/AFP Photo)