A demonstrator catches fire during clashes with riot police within a protest against Venezuelan President Nicolas Maduro, in Caracas on May 3, 2017. Venezuela's angry opposition rallied Wednesday vowing huge street protests against President Nicolas Maduro's plan to rewrite the constitution and accusing him of dodging elections to cling to power despite deadly unrest. (Photo by Ronaldo Schemidt/AFP Photo)

A dancer warms up backstage before the final of the 46th Prix de Lausanne, in Lausanne, Switzerland, 03 February 2018. Launched in 1973, the Prix de Lausanne is an international dance competition for young dancers aged 15 to 18. Closing the six-day event, prizes are awarded to the best of 21 finalists consisting of scholarships granting free tuition in a world-renowned dance school or dance company. (Photo by Valentin Flauraud/EPA/EFE)

Storks that were saved by Bulgarian farmer Safet Ismail are pictured in the village of Zaritsa, Bulgaria, March 21, 2018. Dozens of people from villages in north-eastern Bulgaria took storks to their houses as a lot of the birds got injured due to freezing temperatures and snowfalls in the area over the last few days. (Photo by Stoyan Nenov/Reuters)

A demonstrator holds a rose and shouts slogans in front of a riot policeman during an unauthorized march called by secondary students to protest against government education reforms in Valparaiso, Chile, May 26, 2016. (Photo by Rodrigo Garrido/Reuters)

A young man looks over his shoulder as men watching a soccer match in a nearby bar ask why he isn't watching the game, while walking with his date during the men's gold medal soccer match between Brazil and Germany during Rio 2016 on Saturday, August 20, 2016. (Photo by Aaron Ontiveroz/The Denver Post)

Britain Football Soccer, Burnley vs Swansea City, Premier League, Turf Moor on August 13, 2016. Burnley fan with face paint outside the stadium before the match. (Photo by Ed Sykes/Reuters/Action Images/Livepic)

In this May 12, 2017 photo, Pupy, an African elephant, stands in the doorway of his enclosure at the former city zoo now known as Eco Parque in Buenos Aires, Argentina. A year ago the 140-year old Buenos Aires zoo closed its doors and was transformed into a park. The first director decided that the animals should be housed in buildings that reflected their countries of origin. A replica of a Hindu temple was built for the Asian elephants. (Photo by Natacha Pisarenko/AP Photo)

Subway passengers walk past bronze sculptures representing the Soviet people at the Ploshchad Revolyutsii metro station in Moscow, on November 14, 2012. The station was opened in 1938. (Photo by Kirill Kudryavtsev/AFP Photo)