A participant poses with his laptop during the 33rd Chaos Communication Congress on its opening day on December 27, 2016 in Hamburg, Germany. The annual event is bringing together 12,000 computer hackers and activists who will meet over the next four days to share expertise and discuss topics related to the society and the digital world. (Photo by Morris MacMatzen/Getty Images)

Kira Walkenhorst of Germany (L) signals as Doaa Elghobashy of Egypt (R) watches during the women's Beach Volleyball preliminary pool D game between Ludwig/Walkenhors of Germany and Elghobashy/Nada of Egypt the Rio 2016 Olympic Games at the Beach Volleyball Arena on Copacabana Beach in Rio de Janeiro, Brazil, 07 August 2016. (Photo by Antonio Lacerda/ANSA)

Revelers march in the Lower Ninth Ward during a second line parade marking the 10th anniversary of Hurricane Katrina on August 29, 2015 in New Orleans, Louisiana. (Photo by Mario Tama/Getty Images)

Performers in costume perform in the rain during the parade on the second day of the Notting Hill Carnival in west London on August 31, 2015. Nearly one million people are expected by the organizers Sunday and Monday in the streets of west London's Notting Hill to celebrate Caribbean culture at a carnival considered the largest street demonstration in Europe. The Notting Hill Carnival started in the 1960s, when the area had a large population of immigrants recently arrived from the Caribbean and was notorious for its slums – a far cry from today when it is one of London's most expensive places to live. (Photo by Leon Neal/AFP Photo)

A police officer stands at a police cordon near the scene of a terror attack in London, U.K., on Sunday, June 4, 2017. A van swerved into Saturday-night crowds on London Bridge, before three men got out and went on a stabbing rampage through nearby bars. (Photo by Luke MacGregor/Bloomberg)

A mural signed by “TV Boy” and depicting Pope Francis and U.S. President Donald Trump kissing, is seen on a wall in downtown Rome, Italy on May 11, 2017. (Photo by Tony Gentile/Reuters)

A wide-angle view shows the ascent of the shuttle Challenger on January 28, 1986. In the seconds after ignition, the rocket engines' hot blast began the process of destruction. (Photo by NASA)

Female of pygmy hippopotamus called Malaya from Netherlands in zoo in Dvur Kralove nad Labem, Czech Republic, February 22, 2016. (Photo by David Tanecek/CTK via ZUMA Press)