Participants costumed as zombies try to catch hobby runners during the so-called Zombie-Run at the harness racing track Karlshorst in Berlin, Germany, 18 May 2014. The runners carry small flags in their belts which they have to get safely across the finishing line while the zombies try to steal them. The sporting event is based on the US television series “The Walking Dead”. (Photo by Soeren Stache/DPA)

In this handout image supplied by Qatar 2022 The Al-Rayyan stadium is pictured in this artists impression as Qatar 2022 World Cup bid unveils it's stadiums on September 16, 2010 in Doha, Qatar. It has been designed to include a “media facade” that includes a membrane that acts as a screen for projections; news, commercials, sports updates and current tournament information and matches. (Photo by Qatar 2022 via Getty Images)

Yoga instructor Sarah Henry leads a class during a paddleboard yoga session at Adventure Sports Miami on July 10, 2011 in Miami, Florida. The paddle board is said to give the body's core more of a workout then in a gym since the platform is unstable and one must use the muscles to remain balanced on the board. (Photo by Joe Raedle/Getty Images)

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.

People participate in a wet t-shirt contest on a stage while people party and celebrate on the beach at Clayton's Beach Bar and Grill in South Padre Island, Texas, USA, 11 March 2018. Spring break draws thousands of kids from all over the country to many different locations to celebrate each year. (Photo by Larry W. Smith/EPA/EFE)

A paper mache pig meant to mock Donald Trump sits on display at a protest against the Republican presidential candidate before the start of the Republican National Convention in Cleveland, Ohio, USA, 17 July 2016. Numerous protest groups are expected in Cleveland throughout the four-day-long convention. (Photo by Jim Lo Scalzo/EPA)

Brittnai of El Paso, Texas, USA, performs in the Professional Division Competition during the 5th Annual US Pole Dance Championship on April 1, 2017 at the Symphony Space Theater in New York City. (Photo by Timothy A. Clary/AFP Photo)

A US Army M1A2 SEP tank participates in the Strong Europe Tank Challenge 2017 at the military training area in Grafenwoehr, Germany, 12 May 2017. Six North Atlantic Treaty Organization (NATO) nations and partner nations, Austria, France, Germany, Poland, Ukraine and the USA are taking part in this competing exercise. (Photo by Christian Bruna/EPA)