A farrier attaches a horse shoe still hot from the furnace at The Household Cavalry Mounted Regiment (HCMR) at Hyde Park Barracks on March 28, 2012 in London, England. (Photo by Peter Macdiarmid/Getty Images)

Gloria Lincoln-Thompson carries her 9mm Smith & Wesson pistol in her waistband during a rally in support of the Michigan Open Carry gun law in Romulus, Michigan, in this April 27, 2014 file photo. (Photo by Rebecca Cook/Reuters)

A woman takes a selfie picture as Turkish Kurds gather as part of Newroz celebrations in Diyarbakir, on March 21, 2016. Nowruz, the Farsi-language word for “New Year”, is an ancient Persian festival, celebrated on the first day of spring, on March 21, in Central Asian republics, Iraq, Turkey, Afghanistan and Iran. (Photo by Ilyas Akengin/AFP Photo)

Runner-up; Hon Yen marine ecosystem. Phu Yen, Vietnam. Every year between May and August, the coral of this rich and diverse ecosystem becomes exposed at low tide. (Photo by Truong Hoai Vu/Royal Society of Biology Photography Competition)

A full moon rising over the Re Island Bridge in Rivedoux, France is pictured on December 14, 2016. (Photo by Xavier Leoty/AFP Photo)

An incredible moon rise behind the World Trade Center, Manhattan, New York on August 23, 2016. The breath-taking photo was taken by photographer Jennifer Khordi. She said: it was just absolutely amazing to see this. (Photo by Jennifer Khordi/Caters News Agency)

Sparks are thrown as an employee grinds the edges of a ski at the plant of Swiss ski manufacturer Stoeckli in Malters, Switzerland November 25, 2015. Stoeckli plans to produce some 1,000 pair of skis per year of a special edition for Swiss watch manufacturer TAG Heuer, a brand of LVMH Group. (Photo by Arnd Wiegmann/Reuters)

US marines watch the mushroom cloud from an atomic explosion rise above the Yucca flats, Nevada during a US nuclear weapons test. (Photo by Keystone/Getty Images). USA, 1945