Members of the Coney Island Polar Bear Club warm up before swimming at the beach at Coney Island in New York, December 15, 2013. (Photo by Eric Thayer/Reuters)
Residents wearing facemasks as a preventive measure against the spread of the COVID-19 coronavirus sit in a passenger pick-up on a street in Rawalpindi on March 13, 2020. (Photo by Aamir Qureshi/AFP Photo)
A staff member sets up a ROBOTLEO robot at the Global Mobile Internet Conference (GMIC) 2017 in Beijing, China April 28, 2017. (Photo by Jason Lee/Reuters)
Long row of shiny new Flying Fortresses, part of huge reserves being built up in Britain for D-Day, stands by to be flown to combat units as replacements, May 25, 1944. (Photo by AP Photo)
A snail slithers up a rain spattered window during stormy weather on the Isle of Portland, Fortuneswell, England on July 29, 2018. (Photo by Stuart Fretwell/Rex Features/Shutterstock)
A dog dressed up for a show sits backstage during the 16th annual New York Pet Fashion Show on February 7, 2019 in New York City. (Photo by Johannes Eisele/AFP Photo)
A Siberian eagle owl, which can grow up to 71cm tall, is among a collection of 60 birds of prey at SMJ Falconry near Oxenhope, West Yorkshire, England. (Photo by Charlotte Graham)
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.