A boy rides on a snow wagon towed by a robot dressed as a Teddy bear, which only moves forward by moving its legs, during the Ice and snow carnival at Taoranting park in Beijing February 9, 2015. (Photo by Kim Kyung-Hoon/Reuters)

People dance Tuesday, April 28, 2015, in Baltimore. Maryland's governor vowed there would be no repeat of the looting, arson and vandalism that erupted Monday in some of the city's poorest neighborhoods. (Photo by Matt Rourke/AP Photo)

Alex Plunkett, left, and Sean Hart, both of Arlington, Va., join hundreds participating in the annual International Pillow Fight Day on April 5. Massive pillow fights broke out on the Mall in Washington and in cities around the world. (Photo by Marvin Joseph/The Washington Post)

The Flying Bull's P-38 Lockheed Lightning N25Y / 13 – Red Bull – Flying Legends Airshow 2012 Duxford (Photo by Rob Lovesey)

A little girl takes a picture of a lion in the zoo in Frankfurt, Germany, Tuesday, September 13, 2016. (Photo by Michael Probst/AP Photo)

World War II veterans danced during Victory Day celebrations in Minsk, Belarus, Thursday, May 9, 2013. Belarus and other former Soviet countries celebrated the 1945 victory over Nazi Germany on Thursday. (Photo by Viktor Drachev/AFP Photo)

Trick rider Kendel Sampson performs during the trick riding session of the RAM Rodeo in Warkworth, Ontario, on August 1, 2013. The teenage Encore Presentation Trick Riders perform daring stunts every rodeo season in towns throughout Canada. (Photo by Norm Betts/Barcroft Media)

A Kashmiri Shi'ite Muslim mourner flagellates himself during a Muharram procession to mark Ashura in Srinagar, India October 12, 2016. (Photo by Danish Ismail/Reuters)