A demonstrator throw a firebomb during clashes with Turkish riot police officers in Istanbul, Turkey, Friday, May 1, 2015. The government assigned 30,000 police officers backed by helicopters as workers and demonstrators determined to defy a government ban, tried to march to iconic Taksim Square, where 35 people were killed during May Day celebration in 1977. (Photo by Emrah Gurel/AP Photo)

Mushers and their huskies practice at a forest course ahead of the Aviemore Sled Dog Rally on January 24, 2016 in Feshiebridge, Scotland. Huskies and sledders prepare ahead of the Siberian Husky Club of Great Britain 34th race taking place at Loch Morlich this weekend near Aviemore. (Photo by Jeff J. Mitchell/Getty Images)

People look at a downhill rider during the Urban Bike Inder Medellin race final at the Comuna 1 shantytown in Medellin, Antioquia department, Colombia on November 19, 2017. (Photo by Joaquin Sarmiento/AFP Photo)

A worker looks at an old soviet tank T-34 (L) as he fixes military vehicle (R) at a Phaeton museum in Zaporizhia, Ukraine, August 11, 2015. The museum stopped the restoration works of their collection of about 120 retro autos and motorcycles to help the Ukrainian army to restore military vehicles and equipment which will be used in the conflict in Ukraine eastern regions. (Photo by Gleb Garanich/Reuters)

Tourist Police sit in the shade on a road leading to the Coptic Cairo area on May 27, 2011 in Cairo, Egypt. Protests in January and February brought an end to 30 years of autocratic rule by President Hosni Mubarak who will now face trial. Food prices have doubled and youth unemployment stands at 30%. Tourism is yet to return to pre-uprising levels. (Photo by Peter Macdiarmid/Getty Images)

Ivan Plakhuta, 54, the owner of a small workshop manufacturing valenki, Russian traditional footwear, rolls a valenok in the remote Siberian village of Bolshaya Rechka, located in Taiga area in the foothills of the Western Sayan Mountain Ridge in the Yermakovsky district of Krasnoyarsk region, Russia, November 10, 2015. (Photo by Ilya Naymushin/Reuters)

A performer dressed in costume prepares to participate in the Gay and Lesbian Mardi Gras parade in Sydney, Australia, March 5, 2016. The Sydney Mardi Gras parade began in 1978 as a march and commemoration of the 1969 Stonewall Riots of New York. It is an annual event promoting awareness of gay, lesbian, bisexual and transgender issues and themes. (Photo by David Gray/Reuters)