Participants compete in the Mud Day Race extreme run competition at El Goloso military base, outside Madrid, Spain, June 11, 2016. Thousands of athletes got covered in mud as they celebrated International Mud Day running a 13-kilometer obstacle course on a sunny Saturday with heatwave-like temperatures up to a 29 degrees Celcius (around 84 degrees Fahrenheit). (Photo by Juan Medina/Reuters)

Participants of the Sarenza High Heel Race 2015 warm up prior to the race during a party of the online shoe store, in Paris, Thursday, October 15, 2015. Competitors in teams of three girls race wearing shoes with more than 8 cm-high heels. (Photo by Francois Mori/AP Photo)

Competitors release their hens during the World Championship Hen Racing Championships in Bonsall, Britain August 1, 2015. (Photo by Darren Staples/Reuters)

Competitors ride a home-made vehicle without an engine on a downhill track in the Red Bull Soapbox Race in Santiago, Chile, November 27, 2016. (Photo by Jonathan Faus/Reuters)

The images of U.S. Democratic presidential candidate Hillary Clinton (L) and Republican Presidential candidate Donald Trump are seen painted on decorative pumpkins created by artist John Kettman in LaSalle, Illinois, U.S., June 8, 2016. (Photo by Jim Young/Reuters)

A participant peeks from his costume before the start of the the annual London Pantomime Horse Race in Greenwich, Britain December 13, 2015. (Photo by Neil Hall/Reuters)

A participant competes in the “Nostalgic Ski Race” in the western town of Neuastenberg February 8, 2015. The “Nostalgic Ski Race” is held every two years with about 40 participants and is organized by the ski club of Neuastenberg, a town which was founded in 1713. The conditions for the participation in the race are vintage skis and dresses. (Photo by Ina Fassbender/Reuters)

Participants compete during the Strong Race event near Tukums, Latvia, May 3, 2015. More than 4,000 people participated in this 9 km endurance race with 33 different obstacles. (Photo by Ints Kalnins/Reuters)