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)

Aleksandra Krunic, of Serbia, drops to the court after defeating Petra Kvitova, of the Czech Republic, during the third round of the 2014 U.S. Open tennis tournament, Saturday, August 30, 2014, in New York. (Photo by Kathy Willens/AP Photo)

The Komodo dragon (Varanus komodoensis) was the most popular species overall based on English language Wikipedia page views. It is the world’s largest lizard, living on the islands of Komodo, Rinca and other smaller islands, and on Flores island in Indonesia. (Photo by Eric Nathan/Alamy)

Brazilian Treatment – Mario Testino teams up with American beauty Karlie Kloss for a story lensed in Bahia, Brazil for the July issue of Vogue US. Stylist Phyllis Posnick selects a wardrobe of colorful looks for Karlie to wear as she heads to the beaches and other stunning sights of Bahia. Whether posing with Capoeira dancers or exploring the outdoors, Karlie enchants in every image. (Photo by Mario Testino)

Kim Kardashian arrives for the Thierry Mugler exhibition opening at the Montreal Museum of Fine Arts in Montreal, Chittenango, United States of America on February 26, 2019. (Photo by Splash News and Pictures)

English journalist and newsreader Lucy Watson attends the “Charlie's Angels” UK Premiere at The Curzon Mayfair on November 20, 2019 in London, England. (Photo by Jeff Spicer/Getty Images)

English singer and songwriter Anne-Marie performs on stage during day two of Capital's Jingle Bell Ball with Seat at London's O2 Arena on December 8, 2019. (Photo by Isabel Infantes/PA Images via Getty Images)

Jennifer Lopez stars in the spring-summer 2020 campaign for fashion giant, Versace. The 50-year-old actress appears in the eye-catching campaign, shot by fashion photographers Mert Alas & Marcus Piggott, described by the brand as “a provocation on the power of the internet“. (Photo by Versace/The Mega Agency)