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

A passenger aircraft passes over a residential house as it prepares to land at London Heathrow Airport in west London on October 17, 2016. Britain's government is considering whether to approve a third runway at Heathrow or expand air capacity in southeast England at another airport such as London Gatwick. (Photo by Daniel Leal-Olivas/AFP Photo)

Members of the Gafatar sect walk in the rain as they evacuate their compound, which was later burned down by local villagers, in Antibar village, Mempawah Regency, Indonesia West Kalimantan Province, January 19, 2016 in this photo taken by Antara Foto. Local authorities and police moved the sect members to an army barracks located some 70 km (43 miles) away from Antibar for their safety following recent disputes between the sect and the villagers, Antara said on Tuesday. (Photo by Jessica Helena Wuysang/Reuters/Antara Foto)

Martin Lacey Jr. with a lion during the premiere of the Circus Krone program “Circus der Preistraeger” at Circus Krone on February 2, 2016 in Munich, Germany. (Photo by Hannes Magerstaedt/Getty Images)

A masked reveller parades through the streets on the first day of the carnival season in Lucerne, Switzerland, 12 February 2015. In the background the well known Kappellbruecke bridge. (Photo by Alexandra Wey/EPA)

Elephants spray villagers with water in celebration of the Songkran water festival in Thailand's Ayutthaya province, north of Bangkok, April 10, 2015. The annual elephant Songkran is held to promote the tourism industry prior the Songkran Festival which is celebrated with splashing water and putting powder on each others faces as a symbolic sign of cleansing and washing away the sins from the old year. (Photo by Chaiwat Subprasom/Reuters)

A Saudi soldier fires a mortar towards Houthi movement position, at the Saudi border with Yemen April 21, 2015. (Photo by Reuters/Stringer)

Residents watch the forest burn in Portezuelo, Chile, Sunday, January 29, 2017. Chilean President Michelle Bachelet has announced that the country will continue with its various measures to deal with wild fires, one of the biggest natural disasters in the country for decades, according to a government report released on Sunday. (Photo by Esteban Felix/AP Photo)