Former Olympic gymnast Nastia Liukin performs a flip while throwing the ceremonial first pitch during a baseball game between the Los Angeles Angels and the Tampa Bay Rays, Friday, July 14, 2017, in Anaheim, Calif. (Photo by Jae C. Hong/AP Photo)

Performers Roni, Liv and Becky behind the scenes at Great Yarmouth Hippodrome Circus, England. (Photo by Nick Warner/The Guardian)

Some Iraqi candidates for Miss Iraq beauty contest pose in front of the Ishtar Gate at the ancient archaeological site of Babylon, outside the modern city of Hilla, south of the capital Baghdad on December 17, 2015. The beauty contest, which is the first one in more than 40 years, aims to boost tourism in the city and will take place on December 19, 2015. (Photo by Ahmad Al-Rubaye/AFP Photo)

Young girls attend a training session in MGFSO Olympic reserve school in Moscow on May 30, 2016. (Photo by Kirill Kudryavtsev/AFP Photo)

In this Wednesday, June 8, 2016 photo, Joe Giles, an actor portraying a zombie in “The Walking Dead”, poses with social media reporter Danielle Datu during a walker boot camp at Universal Studios Hollywood in Los Angeles. (Photo by Jae C. Hong/AP Photo)

Stanislav Fursov (top) and Ekaterina Simonova from Russia, who are representing the city of Moscow, dance during the Stage style final round at the Tango World Championship in Buenos Aires, Argentina, August 27, 2015. (Photo by Marcos Brindicci/Reuters)

People ride a Ferris wheel as fireworks illuminate the sky over Edinburgh, Scotland. (Photo by David Cheskin/Press Association)

“Misty Morning”. Every morning, people expect sunny weather. Photo location: Bali, Indonesia. (Photo and caption by Henry Adam/National Geographic Photo Contest)