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.

A woman leaves sauna during the sauna marathon in Otepaa, Estonia on February 2, 2019. Participants have to track down, locate and visit designated saunas in the Otepaa area as fast as possible during the event. The team that completed all of the saunas in the shortest time wins. (Photo by Ints Kalnins/Reuters)

Men watch model trains running along the bar at Bar Ginza Panorama Shibuya Branch on June 3, 2009 in Tokyo, Japan. The bar caters to model train enthusists and customers are able to bring their own model trains to run on the tracks. (Photo by Junko Kimura/Getty Images)

“Glenfinnan Viaduct is a railway viaduct on the West Highland Line in Glenfinnan, Lochaber, Highland, Scotland. It was built between 1897 and 1901. Located at the top of Loch Shiel in the West Highlands of Scotland, the viaduct overlooks the Glenfinnan Monument and the waters of Loch Shiel”. – Wikipedia

Photo: A view of the Glenfinnan Viaduct on March 30, 2012 in Glenfinnan, Scotland. Built by Sir Robert McAlpine, the single track viaduct that is made up of 21 arches is considered to have been one of the largest engineering projects of its time. Today, it is still used by ScotRail and was recently used for scenes in three of the Harry Potter films. (Photo by Jeff J. Mitchell/Getty Images)

Indian commuters travel in a local train in Kolkata, India, Tuesday, February 26, 2013. Indian Railway Minister Pawan Kumar Bansal is presenting the country's rail budget for next fiscal year in the parliament Tuesday, Feb. 26, 2013. Indian railway network is one of the world's largest, with some 14 million passengers daily and some 64,000 kilometers (40,000 miles) of railway track cut through some of the most densely populated cities. (Photo by Bikas Das/AP Photo)

Gerald Herbert is a staff photographer for the AP based in New Orleans, Louisiana. Before that he was a staff photographer for the Washington Times, the New York Daily News and a freelancer for the AP in New Orleans, Boston and New York. Photo: A worker grooms away tracks after an alligator crossed through a sand trap on the 14th hole during the first round of the PGA Tour Zurich Classic golf tournament at TPC Louisiana in Avondale, La., Thursday, April 25, 2013. (Photo by Gerald Herbert/AP Photo)