An unknown number of guns are being built with the mechanisms, causing problems for the police and ATF officials. Photo: An ATF agent holds a generic unfinished receiver, back, and one that has been manufactured, front, at an ATF field office in Washington, on May 06, 2014. The ATF is trying to crack down on the trade in the makeshift guns by targeting shops and individuals who offer to turn the unfinished receivers into functional pieces for firearms. (Photo by Bill O'Leary/The Washington Post)

Abigail Crouse lifts her Thor hammer high after running through Sleeping Beauty's Castle during the Avengers Super Heroes Half Marathon in and around the Disney Parks in Anaheim, California November 16, 2014. Walt Disney Co has moved aggressively into the race business, attracting tens of thousands of runners every year to its marathons, half-marathons and family-friendly races. (Photo by Eugene Garcia/Reuters)

About a dozen dogs traded in their leashes for life vests Saturday for the chance to ride the waves at Jupiter beach as part of a canine surfing competition to raise money for an animal rescue group. Photo: Musso paddles in with Jengo. (Photo by Taylor Jones/The Palm Beach Post)

Masks of Republican presidential candidate Donald Trump (C) and Joaquin "El Chapo" Guzman (2nd L) are seen at Grupo Rev in the Mexican city of Cuernavaca near Mexico City, October 14, 2015. (Photo by Henry Romero/Reuters)

Ralph Mirebs, an urban explorer and photographer in Russia, has revealed extraordinary photos of Soviet space shuttle prototypes gathering dust in an abandoned hangar. The abandoned hangar is located at the Baikonur Cosmodrome in Kazakhstan, which is still in operation today (with the close of NASA’s shuttle program, Russian Soyuz shuttles are the only way for astronauts to reach the International Space Station). The Buran prototype shuttles found by Mirebs, however, are from an earlier era – they are the last remnants of a space program that began in 1974 and was finally shuttered in 1993. (Photo by Ralph Mirebs/Exclusivepix Media)

Tank crew standing in front of M-4 tank, Ft. Knox, Kentucky, June, 1942. (Alfred Palmer/OWI/LOC)

Sierra “Lovely Amazin” Redd of Greensboro, North Carolina, poses for bikers by a custom Suzuki Katana on Ocean Boulevard during the 2015 Atlantic Beach Memorial Day BikeFest in Myrtle Beach, South Carolina May 24, 2015. (Photo by Randall Hill/Reuters)

President Donald Trump speaks at a campaign rally at Duluth International Airport, Wednesday, September 30, 2020, in Duluth, Minn. (Photo by Alex Brandon/AP Photo)