Engine driver Josef Kowatsch (top L) steers a train through the NEAT Gotthard Base Tunnel during a media visit near the town of Erstfeld August 24, 2015. Crossing the Alps, the world's longest train tunnel should become operational at the end of 2016, consisting of two parallel single track tunnels, each of a length of 57 km (35 miles). (Photo by Arnd Wiegmann/Reuters)

Construction workers take a lunch break on a steel beam atop the RCA Building at Rockefeller Center, New York, September 29, 1932. In the background is the Chrysler Building. (Photo by AP Photo)

Rebels of the Revolutionary Armed Forces of Colombia (FARC) visit as they wait to have lunch in El Diamante, Colombia, Friday, September 16, 2016. FARC rebels are gathering for a congress were delegates will debate and vote on the accord reached last month with the Colombian government to end five decades of war. (Photo by Ricardo Mazalan/AP Photo)

A vendor smokes behind a display of dog meat at a dog meat market on the day of a local dog meat festival in Yulin, Guangxi Autonomous Region, June 22, 2015. (Photo by Kim Kyung-Hoon/Reuters)

A girl collects drinking water at Dala river outside Yangon, Myanmar March 3, 2016. Some 650 million people, or one in 10 of the world's population, have no access to safe water, putting them at risk of infectious diseases and premature death. Dirty water and poor sanitation can cause severe diarrhoeal diseases in children, killing 900 under-five a day across the world, according to United Nations estimates. (Photo by Soe Zeya Tun/Reuters)

A girl jumps over a campfire while celebrating Ivan Kupala Night, a traditional Slavic holiday not far from Kiev on July 6, 2013. During the celebration, originating in pagan times, people plait wreaths, jump over fires, and swim naked. (Photo by Sergei Supinsky/AFP Photo)

Russian army soldiers, dressed in WWII era uniforms, march along the Red Square during a general rehearsal for the Victory Day military parade which will take place at Moscow's Red Square on May 9 to celebrate 70 years after the victory in WWII, in Moscow, Russia, Thursday, May 7, 2015. (Photo by Ivan Sekretarev/AP Photo)

Participants ride horses, hold spears and wear historic armoured suits of the Middle Ages as they compete during the Saint George international knight tournament in Moscow, Russia, May 3, 2015. (Photo by Maxim Zmeyev/Reuters)