A member of the United States Naval Academy freshman class wears body armor, helmet and carries a rifle through a mud-filled ditch as part of the “Wet and Sandy” challenge during the rigorous Sea Trials May 17, 2011 in Annapolis, MD. Under strict safety supervision, about 900 freshmen, or “Plebes”, faced 14 hours of 32 rigorous physical and mental challenges during the trials, a daylong, action-oriented event modeled after the Marine Corps 54-hour Crucible and the Navy's Battle Stations. (Photo by Chip Somodevilla/Getty Images)

Model Amanda Kaspor of Highland, Michigan poses with the CT&T e-Zone Plus electric car is displayed during the press preview for the world automotive media North American International Auto Show at the Cobo Center January 12, 2010 in Detroit, Michigan. (Photo by Bryan Mitchell/Getty Images)

Mike “The Bedfordshire Bull Botteley” (left) takes on Chris “The General” Levy during a Chessboxing bout at the Scala nightclub on March 10, 2012 in London, England. A new hybrid sport combining chess and boxing in alternate 3 minute rounds, the winner is the one who knocks out or checkmates their opponent first. (Photo by Matthew Lloyd/Getty Images)

Monsoon thunderstorm in Sierra Vista, Arizona. 9 Sept, 2011. (Photo by Steven Maguire)

“APOPO’s Training Center, situated on Sokoine Univeristy of Agriculture (SUA) in Tanzania, was established in 2000 to accommodate training and testing of mine detection rats in near-to-real conditions”. – APOPO

Photo: MDR (Mine Detection Rat) learn to look for mines. (Photo by APOPO's HeroRATs)

A “scissors” dancer grabs her shoe with her mouth while performing in a national scissors dance competition in the outskirts of Lima December 1, 2013. The Danza de las tijeras, or scissors dance, is a traditional dance from the Peruvian southern region of the Andes, in which two or more performers take turns dancing while accompanied with music from a harp and a violin. Dancers would display various skills and moves, which include cutting the air with the use of a scissors. (Photo by Enrique Castro-Mendivil/Reuters)

A young Matachin dancer sits on a the side during the annual pilgrimage in honor of Mexico's patron saint the Virgin of Guadalupe in Ciudad Juarez, Mexico, December 12, 2016. (Photo by Jose Luis Gonzalez/Reuters)

Purev and Buyantogtokh enjoy the warmth of the fire in the snow in Altai Mountains, Mongolia, September 2016. Navigate the snowy wilds of Mongolia with this nomadic reindeer herding family. Photographer Joel Santos dived 1000km into the depths of Northern Mongolia to visit the Ganbaa family near Khovsgol Lake. (Photo by Joel Santos/Barcroft Images)