Emma White, of Team Cyclocrossworld, hits the dirt hard during the USA Cycling Cyclo-cross National Championship Elite Women's race at the Valmont Bike Park in Boulder, Colorado, on January 12, 2014. (Photo by Jeremy Papasso/The Daily Camera)

Revellers pose during the 24th Street Parade dance music event in Zurich, August 29, 2015. (Photo by Arnd Wiegmann/Reuters)

India's Border Security Force (BSF) “Daredevils” motorcycle riders perform during a rehearsal for the Republic Day parade on a foggy winter morning in New Delhi January 8, 2015. India will celebrate its annual Republic Day on January 26. (Photo by Ahmad Masood/Reuters)

Opossums on their mothers back at a game reserve in Central Minnesota, USA, on September 2, 2013. (Photo by Caters News Agency)

The Arabian mare “Jenny” curiously sniffs at the child of Raphael Wöllstein, who is on his way to the train, on her daily walk through the Fechenheim district of Frankfurt, Germany on March 8, 2019. Her owner opens the stable door for the 22-year-old horse every morning. Then the animal can decide for itself where it wants to spend the day. So that nobody thinks she's escaped, a sign with the inscription “My name is Jenny, didn't run away, just go for a walk” is on the halter. (Photo by Boris Roessler/dpa)

A military band prepares to play the national anthems before Cuban President Raul Castro welcomes U.S. President Barack Obama at the Palacio de la Revolucion in Havana March 21, 2016. Barack Obama on Sunday became the first US president in 88 years to visit Cuba, touching down in Havana for a landmark trip aimed at ending decades of Cold War animosity. (Photo by Jonathan Ernst/Reuters)

A competitor shouts as he takes part in the “Tough Guy” adventure race near Wolverhampton, central England, on January 29, 2017. The Tough Guy event, which is being held for the final time in its 30th year, challenges thousands of competitors to run a gruelling course whilst negotiating over 200 obstacles including: water, fire, and tunnels. (Photo by Oli Scarff/AFP Photo)

Men slide in the mud during the Boryeong Mud Festival at Daecheon Beach in Boryeong, South Korea, Saturday, July 22, 2017. The 20th annual mud festival features mud wrestling and mud sliding. (Photo by Ahn Young-joon/AP Photo)