A hippopotamus performs during a show at the circus in Krasnoyarsk, Siberia, Russia, July 7, 2016. (Photo by Ilya Naymushin/Reuters)

2016 Rio Olympics, Gymnastics training, Rio Olympic Arena, Rio de Janeiro, Brazil on August 4, 2016. Close up of the feet of Rebecca Downie (GBR) of United Kingdom as she trains on the beam. (Photo by Dylan Martinez/Reuters)

A news reporter doing a stand up near a sea wall in Cedar Key, Fla., is covered by an unexpected wave as Hurricane Hermine nears the Florida coast, Thursday, September 1, 2016. Hurricane Hermine gained new strength Thursday evening and roared ever closer to Florida's Gulf Coast, where rough surf began smashing against docks and boathouses and people braced for the first direct hit on the state from a hurricane in over a decade. (Photo by John Raoux/AP Photo)

A girl walks in front of a graffiti painted on the wall of a house located inside the 15th-century complex built by Mameluk Sultan al-Ashraf Qaitbey, in Cairo's City of the Dead, Egypt February 13, 2017. (Photo by Amr Abdallah Dalsh/Reuters)

The possible surface of TRAPPIST-1f, one of seven newly discovered planets in the TRAPPIST-1 system that scientists using the Spitzer Space Telescope and ground based telescopes have discovered. (Photo by Reuters/NASA/JPL-Caltech)

Ferrari driver Fabio Barone and his Ferrari 458 Italia competes against a Roman chariot drawn by two horses on “Ben Hur” movie set at Cinecitta World amusement park on May 11, 2017 in Castel Romano near Rome. (Photo by Andreas Solaro/AFP Photo)

Two female soldiers have their picture taken by an army colleague at Mangyongdae. (Photo by Gavin John/Mediadrumworld.com)

Staff of a boat restaurant on the Taedong River line up at the entrance as they wait to greet customers Sunday, June 18, 2017, in Pyongyang, North Korea. The boat is berthed along the river, which is the fifth longest river on the Korean Peninsula and runs through the country's capital, Pyongyang. (Photo by Wong Maye-E/AP Photo)