2016 Rio Olympics, Beach Volleyball, Women's Preliminary, Beach Volleyball Arena, Rio de Janeiro, Brazil on August 6, 2016. Liliana Fernandez Steiner (ESP) of Spain prepares to serve. (Photo by Ruben Sprich/Reuters)

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.

Japan' s Kaori Sakamoto competes in the women' s single skating short program of the figure skating event during the Pyeongchang 2018 Winter Olympic Games at the Gangneung Ice Arena in Gangneung on February 21, 2018. (Photo by John Sibley/Reuters)

Resident Taina holds her brother Ysaque in the hallway outside their apartment in an occupied building in the Mangueira “favela” community on August 13, 2016 in Rio de Janeiro, Brazil. (Photo by Mario Tama/Getty Images)

Artists perform during the Closing Ceremony of the Rio 2016 Olympic Games at the Maracana Stadium in Rio de Janeiro, Brazil, 21 August 2016. (Photo by Sergei Ilnitsky/EPA)

The Sphinx breed of cat “Adam vom Feisastern” of the German breeder Sabine Braeuer waits on a jury table during an annual International Pedigree Dog and Cat Show in Erfurt, Germany on June 10, 2012. (Photo by Jens Meyer/Associated Press)

“The 8th annual Water War on Friday in the center of Tel-Aviv, Israel turned into a battlefield, quite literally. As two thousand people were having fun in the square, some water-fighters took to more radical behavior, targeting passing cars, motorcycles and public buses”. – iReport.cnn.com (Photo by Sergey Demyanchuk)