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)

The Florida Keys are famous for their diving, but they are less well known for another quirky attraction: the mailboxes residents use to decorate their driveways. From a fiberglass manatee in lipstick to a small white church, Reuters photographer Wolfgang Rattay documented this unusual aspect of local culture as he drove along the Ocean Highway that connects the islands. Photo: A mailbox in the shape of a fire truck is seen along the highway US-1 in the Lower Keys near Marathon in Florida, July 11, 2014. (Photo by Wolfgang Rattay/Reuters)

Have you ever heard of a psychological phenomenon which lets us easily understand words, even if the order of letters is mixed up, as long as the first and last letters remain in their rightful place? Similarly, the art works of Michael Turner use only two colors to highlight the main futures of well-recognized superheroes, allowing our imagination to create the rest of the picture. The colors used in the pictures weren’t chosen at random. They perfectly reflect the key characteristics of the superheroes that they depict. For example, the picture of Flash uses red and yellow colors, which are exactly the colors of his costume. While the picture of Green Lantern is, you’ve guessed it, green and black. (Photo by Michael Turner)

With more than 40,000 followers on Twitter and 26,400 fans on Vine, it looks like Marutaro the hedgehog from Japan is one of the most popular hedgehogs on the Internet. And as his owner keeps on posting Marutaro’s pictures online daily, Marutaro’s popularity continues to grow. There are hundreds of cute photographs and videos of this little fellow, but the ones with little paper cut-out faces are probably the cutest. As Marutaro lies on his back, his owner gives him a variety of silly expressions and smiles. The 20 best of them will definitely boost your mood!

Worth 1000`s photoshop contest for making the best celebrity mug shot