Policemen detain topless activists of women's rights group Femen, who stage a performance during a protest against Ukrainian President Petro Poroshenko and the government while marking the Day of Dignity and Freedom near the presidential administration headquarters in Kiev, Ukraine November 21, 2017. (Photo by Valentyn Ogirenko/Reuters)

An undated handout image provided by UNICEF Germany on 20 December 2016 shows the “UNICEF Photo of the Year 2016” by Iranian freelance photographer Arez Ghaderi. Ghaderi won the first prize for his picture of a girl in a makeshift tent city in the Razavi Khorasan province, Iran, it was announced at a ceremony in Berlin, Germany on 20 December 2016. (Photo by Ariz Ghaderi/EPA/UNICEF Deutschland)

Blankets cover the bodies of a woman (right) and a man (left background) hit by a northbound Penn Central train (background) as they waited with a crowd at Pennsylvania Railroad station in Elizabeth, N.J. on June 8, 1968 to view the southbound train carrying the body of Sen. Robert F. Kennedy to Washington. The woman was identified as Mrs. Antoinette Severini, 54, and the man, John Curia (age unavailable), both of Elizabeth. (Photo by AP Photo)

A man rides a horse through flames during the annual “Luminarias” celebration on the eve of Saint Anthony's day, Spain's patron saint of animals, in the village of San Bartolome de Pinares, northwest of Madrid, Spain, January 16, 2017. (Photo by Paul Hanna/Reuters)

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 masked participant carries a burning matress during the ancient carnival of Zubieta, in the northern Spanish Navarra province on January 30, 2018. The yearly three day festivities, revolving mainly around agriculture and principally sheep hearding, run on the last Sunday, Monday and Tuesday of January where Navarra Valley locals from two villages dress up and participate in a variety of activites as they perform a pilgrimage through each village. (Photo by Ander Gillenea/AFP Photo)

In this January 11, 2018 photo, a skater jumps a ramp during the inauguration of a new recreational space for skateboarders, created in an abandoned gym at the Educational complex Ciudad Libertad, a former military barracks that the late Fidel Castro turned into a school complex after the revolution in Havana, Cuba. Foreign skateboard enthusiasts supply their Cuban counterparts with boards and other equipment. (Photo by Ramon Espinosa/AP 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)