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.

Russian soldiers write home while serving on the Eastern Front during World War I, circa 1915. (Photo by Hulton Archive/Getty Images)

Actress Marilyn Monroe poses for a portrait in a bathing suit and high heels with a bottle of Coca-Cola in a glass on a table behind her in circa 1953. (Photo by Michael Ochs Archives/Getty Images)

Tourists enjoy hot pot and spring at the hotpot shaped spring during winter at a hotel in Hangzhou, east China's Zhejiang Province on December 26, 2018. (Photo by Sipa Asia/Rex Features/Shutterstock)

A woman cries while being escorted by police officers during an anti-government protest in Santiago, Chile, 07 November 2019. A proposed increase in the price of metro fares sparked a series of anti-government protests that have left at least 20 people dead. The protestors are demanding improvements in the quality of healthcare, education and general distribution of wealth in Chile. (Photo by Orlando Barría/EPA/EFE)

A Palestinian man carries a lion cub as he shows it to children in Rafah refugee camp in the southern Gaza Strip on December 4, 2019. (Photo by Ibraheem Abu Mustafa/Reuters)

Shannon Courtenay exchanges punches with Buchra El Quaissi during the Bantamweight between Shannon Courtenay and Buchra El Quaissi at York Hall on December 19, 2019 in London, England. (Photo by James Chance/Getty Images)

A monkey chews on a brazillian tourist's hair at the Pra Prang Sam Yod temple during the Lopburi Monkey Festival on November 28, 2021 in Lop Buri, Thailand. Lopburi holds its annual Monkey Festival where local citizens and tourists gather to provide a banquet to the thousands of long-tailed macaques that live in central Lopburi. (Photo by Lauren DeCicca/Getty Images)