Roped up climbers leave the summit of Breithorn at 4,164 metres (13,661 feet) on the ridge marking the border with Switzerland (left) and Italy in the Alpine resort of Zermatt August 4, 2014. Switzerland will vote on November 30 on an initiative from the group Ecopop which proposes a cap on the number of immigrants. The group says it is motivated by concerns about a lack of living space exerting too much pressure on the land and natural resources, rather than by opposition to foreigners. (Photo by Denis Balibouse/Reuters)

Tsar Alexander II (1818–1881) known as “The Liberator” lying in state. He was mortally wounded by an assassination attack in St Petersburg. (Photo by Hulton Archive/Getty Images). March 1881

Two guards perform an execution in China, one holding the gun, the other holding a mask over the victim's face. (Photo by General Photographic Agency/Getty Images). Circa 1925

Clutching a large paper bag and shading his eyes as he peers ahead, comic actor of the silent screen, Buster Keaton (1885–1966) arriving at Paris airport. (Photo by Keystone/Getty Images). 1st August 1947

Ruins of a building are seen in the old village of Belchite, in northern Spain, November 13, 2016. Almost 80 years ago Tomas Ortin fled under the cover of night from his home in the small town of Belchite on Spain's northern plains to escape with hundreds of others from one of the bloodiest battles of the country's civil war. At 94 years old, Ortin now lives just across the road from Belchite, which has lain in ruins since Republican forces attacked it, a symbol of the destruction caused by the 1936-1939 war in which an estimated 500,000 people died. (Photo by Andrea Comas/Reuters)

This photo taken on March 29, 2017 shows a young woman offering shots of liquer at a dance bar in Walking Street in Pattaya. Two hours east of Bangkok, Pattaya's bawdy reputation hails from the Vietnam War era when US GIs partied in their downtime. (Photo by Roberto Schmidt/AFP Photo)

A student is assisted by teachers after she fell ill while marching in a parade celebrating Saint Peter's day in Lima, Peru, Monday, June 29, 2015. During the feast day of the Catholic saint, who is the patron saint of fishermen, coastal communities pay homage to St. Peter, whose statue is paraded to the sea and petitions are made to keep their vessels and all who work on them safe. (Photo by Rodrigo Abd/AP Photo)

A woman walks in central Rason city, northeast of Pyongyang, August 29, 2011. (Photo by Carlos Barria/Reuters)