Participants wear traditional clogs as shepherds lead their sheep through the center of Madrid, October 28, 2012. (Photo by Andres Kudacki/Associated Press)

Groupama Sailing Team, skippered by Franck Cammas of France during leg 1 of the Volvo Ocean Race to Cape Town on November 6, 2011. (Photo by Yann Riou/Groupama Sailing Team/Volvo Ocean Race via Getty Images)

A young anoa, also known as midget buffalo, named Tycoon runs around at the Zoo in Berlin, Germany, on November 9, 2012. (Photo by Maurizio Gambarini/EPA)

Clown/comedian/filmmaker Pierre Etaix attends The Academy Of Motion Picture Arts And Sciences' Presents “Pierre Etaix: The Laughter Returns” at AMPAS Samuel Goldwyn Theater on November 16, 2011 in Beverly Hills, California. (Photo by Valerie Macon/Getty Images)

In this handout photo provided by Warner Brothers Pictures and Village Roadshow Pictures, Tom Cruise plays Lieutenant Colonel Bill Cage, a soldier who replays his last day while trying to fight aliens, in director Doug Liman's “All You Need Is Kill”. The film is set to premiere on March 14, 2014. (Photo by David James/Warner Brothers Pictures)

A mass pillow fight in Trafalgar Square in central London on April 5, 2014 on International Pillow Fight Day. (Photo by Jane Scanlan)

The competition, which is run by the Royal Observatory Greenwich in association with BBC Sky at Night Magazine, is now in its sixth year and has received over 2,500 entries. Photo: Centre of the Heart Nebula by Ivan Eder (Hungary). Situated 7500 light years away in the “W”-shaped constellation of Cassiopeia, the Heart Nebula is a vast region of glowing gas, energized by a cluster of young stars at its centre. The image depicts the central region, where dust clouds are being eroded and moulded into rugged shapes by the searing cosmic radiation. (Photo by Ivan Eder)

Skeleton involves a person riding a small sled down a frozen track while lying face down. The sport is a more intense form of luge because skeleton competitors leap onto the sled and slide downhill head first. Skeleton athletes can reach up to 80 mph on straightaways, causing forces up to 5g, so the helmet is a critical component for attitude as well as safety.