A man demonstrates outside Republican presidential candidate Donald Trump's news conference at Trump Tower in New York, U.S., May 31, 2016. (Photo by Shannon Stapleton/Reuters)

Participants run through coloured powder during the YARKOcross colour run race in Almaty, Kazakhstan, June 5, 2016. (Photo by Shamil Zhumatov/Reuters)

A Nepalese army solder stand next to a horse during the “Ghodejatra” Horse Race festival, which is organised by the Nepal Army, in Kathmandu, Nepal, April 7, 2016. Ghode Jatra, the horse racing festival of Nepal, celebrated on the New Moon day of mid March or early April is among the important celebrations of the Kathmandu Valley. Grand horse parade including various acrobatic style of shows are performed by Nepal military at Tundikhel-a fenced parade ground located in the heart of Kathmandu city. (Photo by Navesh Chitrakar/Reuters)

A bull savar (jockey) jumps off his tray as he competes in a bull race in Pind Sultani, Pakistan January 31, 2017. (Photo by Caren Firouz/Reuters)

Pigs race around the track at the Pig Racing and Diving display at the Sydney Royal Easter Show on April 10, 2009 in Sydney, Australia. (Photo by Mark Kolbe/Getty Images)

People attend the Stranavigli Water Race held at the Naviglio Grande on July 16, 2011 in Milan, Italy. Stranavigli Water Race is an annual creative contest on the water. (Photo by Vittorio Zunino Celotto/Getty Images)

Hollowed pumpkins float on a lake Ludwigsburg Castle on September 19, 2010 in Ludwigsburg, Germany. (Photo by Ralph Orlowski/Getty Images)

Participants sit on a cable chair as they take part in the 30th edition of the Belalp Witches Ski Race on January 14, 2012 in Belalp, Switzerland. The race is inspired by a legend dating back to the middle ages, of a witch who tormented villagers in the area until she was burnt to death. (Photo by Harold Cunningham/Getty Images)