The Boeoegg, a giant symbolic snowman made of wadding and and filled with firecrackers burns on top of a bonfire in Sechselaeuten square on April 24, 2017 in Zurich. When the bells of the Saint Peter's church chime six o'clock, the bonfire under the snowman is set in fire and the guildsmen wearing historical costumes ride around the bonfire. The faster the head of the snowman explods the warmer and more beautiful the summer will be. (Photo by Michael Buholzer/AFP Photo)

Up to 35% of Mongolians still live a nomadic life, depending on their land to survive. But environmental changes, particularly desertification, means this way of life is under threat. Korean photographer Daesung Lee’s Futuristic Archaeology images show billboard-size backdrops of lush steppe contrasting with actual scenery as former nomads enact scenes of hunting, herding and Mongolian wrestling. (Photo by Daesung Lee)

A team of Irish dancers celebrate after winning the under 12's group kaylee World Irish Dance Championship on April 2, 2016 in Brighton, England. The 8th World and 11th European Irish Dance Championships sees over 1500 dancers from 26 countries, speaking over 20 languages, competing in a variety of contests at the Brighton Centre on the city's beachfront. The event is organised by the World Irish Dance Association and is billed as the “Irish Dance Spectacular”. (Photo by Chris Ratcliffe/Getty Images)

A boy crawls under a cow during a religious ceremony celebrating the Tihar festival, also called Diwali, in Kathmandu, October 23, 2014. Hindus all over Nepal are celebrating the festival during which they worship cows, which are considered a maternal figure, and other animals. Also known as the festival of lights, devotees worship the goddess of wealth Laxmi by illuminating and decorating their homes using garlands, oil lamps, candles and colourful light bulbs. (Photo by Navesh Chitrakar/Reuters)

Travellers ride their horse through the river during the Appleby Horse Fair on June 5, 2014 in Appleby, England. The Appleby Horse Fair has existed under the protection of a charter granted by James II since 1685 and is one of the key gathering points for the Romany, gypsy and traveling community. The fair is attended by about 5,000 travellers who come to buy and sell horses. The animals are washed and groomed before being ridden at high speed along the “mad mile” for the viewing of potential buyers. (Photo by Nigel Roddis/Getty Images)

Soldiers use electronic sensors to search for missing firefighters under a line of fire trucks caught in massive gas explosions in Kaohsiung, Taiwan, Friday, August 1, 2014. A series of underground explosions about midnight Thursday and early Friday ripped through Taiwan's second-largest city, killing scores of people, Taiwan's National Fire Agency said Friday. (Photo by Wally Santana/AP Photo)

Supporters and opponents of Russian opposition activist and anti-corruption crusader Alexei Navalny clash during unsanctioned protest in Manezhnaya Square in Moscow, Russia, Tuesday, December 30, 2014. The unsanctioned protest came hours after Alexei Navalny was found guilty of fraud and given a suspended sentence. Navalny, who has been under house arrest since February, is accused of breaking the terms of his house arrest to attend the rally and was detained by police as he approached the site of the protest. (Photo by Ivan Sekretarev/AP Photo)