Emma White, of Team Cyclocrossworld, hits the dirt hard during the USA Cycling Cyclo-cross National Championship Elite Women's race at the Valmont Bike Park in Boulder, Colorado, on January 12, 2014. (Photo by Jeremy Papasso/The Daily Camera)

An Israeli woman scrambles through the mud and under barbed wire at the competition of the Legion Run in the Menara Cliffs area of Kiryat Shmona, in northern Israel, near the Lebanon border 14 October 2016. Hundreds of participants ran five kilometers cross country in steep terrain and then navigated various obstacle courses including steep inclines and mud holes. It is the first time this non-competitive but supportive sporting event is held in Israel. (Photo by Jim Hollander/EPA)

America in the 1970s: Texas. Motorcyclist loading his possessions onto a truck with the help of his friends in Leakey, May 1973. (Photo by Marc St. Gil/NARA via The Atlantic)

Emma Watson attends the Elle Style Awards 2014 at one Embankment on February 18, 2014 in London, England. (Photo by Tim P. Whitby/Getty Images)

This undated photo shows the Arctic National Wildlife Refuge in Alaska. (Photo by U.S. Fish and Wildlife Service/Getty Images)

Maria Sharapova of Russia arrives at the 2012 Australian open Players Party at Crown Towers on January 15, 2012 in Melbourne, Australia. (Photo by Robert Prezioso/Getty Images)

Attendee Emily poses for a picture at 2017 Comic-Con International on July 20, 2017 in San Diego, California. (Photo by Mike Blake/Reuters)