Greyhounds compete during a race at Santiago city, March 8, 2014. With over 100 years of history, greyhound racing attracts people mainly from rural areas of Santiago every weekend. Some dogs come from Argentina, the United States and Ireland and can develop a speed of up to 80 kilometers per hour on a straight running track of about 200 meters, according to organisers. Bets range from $2 to $1,000 per race, offering a livelihood for breeders and gamblers. (Photo by Ivan Alvarado/Reuters)

Participants cross cold and muddy waters during the Strong Race competition near Tukums May 4, 2014. About 6500 people competed in this extreme running race, which includes cross-country running, elements of agility and power discipline. (Photo by Ints Kalnins/Reuters)

Competitors in action during a qualifying heat for the 12 hour Lawn Mower Endurance Race on September 24, 2011 in Billingshurst, England. First started in 1973 as a motorsport that would be accessible to as many as possible, there is little commercialism or sponsorship, no cash prizes and no modifying of engines. The trophies are donated from various sources with famous names such as Sir Stirling Moss found engraved on the plaques from previous races. (Photo by Matthew Lloyd/Getty Images)

A competitor reacts as she emerges from the water during the Tough Guy event in Perton, central England, January 26, 2014. The annual Tough Guy race – “the toughest race in the world” – at Perton in Staffordshire. Tough Guy claims to be the world’s most demanding one-day survival ordeal. First staged in 1987, the Tough Guy Challenge has been widely described as one of the hardest races of it’s type with up to one-third of the starters failing to finish in a typical year. (Photo by Darren Staples/Reuters)

A competitor loses his shoe during the annual race on high heels during Gay Pride celebrations in the quarter of Chueca in Madrid, Spain, June 30, 2016. (Photo by Susana Vera/Reuters)

Farmer Franz Schaller rides on an ox called Napoleon during a traditional ox race in the southern Bavarian village of Muensing near Lake Starnberg, Germany August 28, 2016. (Photo by Michaela Rehle/Reuters)

Britain's Chris Froome, wearing the overall leader's yellow jersey, is followed by Spain's Alberto Losada, Italy's Vincenzo Nibali and Spain's Alejandro Valverde as they speed downhill during the seventeenth stage of the Tour de France cycling race over 161 kilometers (100 miles) with start in Digne-les-Bains and finish in Pra Loup, France, Wednesday, July 22, 2015. (Photo by Christophe Ena/AP Photo)