People slide down a 1,082 feet (330 metre) long inflatable water slide in Hong Kong, China August 22, 2015. (Photo by Tyrone Siu/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.

Pedestrians and workers pass an upside down car art installation in a car park on the South Bank in London, February 19, 2015. British artist Alex Chinneck's illusory piece, entitled “Pick yourself up and pull yourself together”, and on display in the working car park for a week, sees a Vauxhall car suspended upside down, appearing to be gripping onto a peeled back length of tarmac. (Photo by Toby Melville/Reuters)

Parade goers draped in American flags walk down the street before a Fourth of July parade begins Saturday, July 4, 2020, in Bristol, R.I. The town, which lays claim to the nation's oldest Independence Day celebration in the country, held a vehicle-only scaled down version of its annual parade Saturday due to the coronavirus pandemic. (Photo by David Goldman/AP Photo)

In this photo taken with long time exposure, a woman wears a hat at Churchill Downs before the 145th running of the Kentucky Derby horse race Saturday, May 4, 2019, in Louisville, Ky. (Photo by Charlie Riedel/AP Photo)

Buyan, a male Siberian brown bear, cools down under a stream of water sprayed by an employee in an enclosure on a hot summer day, at the Royev Ruchey zoo in Krasnoyarsk, Russia on June 14, 2019. (Photo by Ilya Naymushin/Reuters)

Spectators cheer after Medina Spirit, ridden by John Velazquez wins 147th Kentucky Derby at. Churchill Downs, in Louisville, Kentucky, U.S. May 1, 2021. (Photo by Bryan Woolston/Reuters)

Buyan, a male Siberian brown bear, cools down under a stream of water sprayed by an employee in an enclosure on a hot summer day, at the Royev Ruchey zoo in Krasnoyarsk, Russia on June 14, 2019. (Photo by Ilya Naymushin/Reuters)