Ahmed, a 10-year-old jockey, looks on during the opening of the International Camel Racing festival at the Sarabium desert in Ismailia, Egypt, March 21, 2017. (Photo by Amr Abdallah Dalsh/Reuters)

Participants arrive at the finish line during the annual Maldon Mud Race in Maldon, east England on May 7, 2017. Originating in 1973, the race involves competitors racing around a course through the River Blackwater in Essex at low tide. (Photo by Daniel Leal-Olivas/AFP Photo)

Participants wearing historical costumes ride their high-wheel bicycles during the annual penny farthing race in Prague, Czech Republic November 5, 2016. (Photo by David W. Cerny/Reuters)

A Husky dog looks on before a sled and skijoring race in the village of Kadnikovo outside Yekaterinburg, Russia, December 10, 2016. (Photo by Maxim Shemetov/Reuters)

A pet horse tethered on land known as “The Cracker” in Tipton that may be seized by bailiffs on October 10, 2011 in Dudley, England. Horse lovers in Tipton are battling the local council over the tradition of keeping their horses tethered on public land near their homes. Locals say tradition that has been in existence for generations and believe it stems from the age of the canal when many local men used their horses to tow canal barges along the industrial Black Country canals. After a spate of horses running free Sandwell Council are now enforcing the law and impounding tethered horses. Locals are planning their next protest with a horse drive to the council headquarters to try and save their traditions. (Photo by Christopher Furlong/Getty Images)

In this January 7, 2017 photo, Judeley Hans Debel squats down to remove a boot from Tic Tac, holding out his prosthetic leg after his therapeutic riding lesson at the Chateaublond Equestrian Center in Petion-Ville, Haiti. Anne-Rose Schoen, who founded the equestrian center, said perhaps the most important thing about therapeutic riding is it makes youngsters happy in a country where disabled people face enormous challenges. (Photo by Dieu Nalio Chery/AP Photo)

People watch a competitor riding a homemade vehicle without an engine on a 300-metre-track during the Red Bull Soapbox Race in Amman, Jordan September 4, 2015. (Photo by Muhammad Hamed/Reuters)

Participants take part in the Mud Day race, a 13km obstacle course, on March 24, 2017 in the Israeli Mediterranean coastal city of Tel Aviv. (Photo by Jack Guez/AFP Photo)