The two Pulis Quastie and Gin-Gin run in the snow in their garden in Lautertal, southern Germany, Thursday, January 5, 2017. (Photo by Michael Probst/AP Photo)

An artist's impression of a growing supermassive black hole located in the early Universe is seen in this NASA handout illustration released on June 15, 2011. Using the deepest X-ray image ever taken, astronomers found the first direct evidence that massive black holes were common in the early universe. This discovery from NASA's Chandra X-Ray Observatory shows that very young black holes grew more aggressively than previously thought, in tandem with the growth of their host galaxies. (Photo by Reuters/NASA/Chandra X-Ray Observatory/A.Hobart)

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)

Second Place Winner: “Thunderstorm at False Kiva”. I hiked out to these ruins at night hoping to photograph them with the Milky Way, but instead a thunderstorm rolled through, creating this dramatic image. – Max Seigal. National Geographic Traveler Director of Photography Dan Westergren, one of this year's judges, shares his thoughts on the second place winner: “This photo combines two different scenes into one: the small kiva in a cliff dwelling and the grand vista of Canyonlands National Park across the valley. I really like the two different color palettes – warm inside and purple outside. This two-for-one scene was caused by the lightning storm outside the dwelling, which lit up the landscape like it was a huge electronic flash. Looking at this picture I can imagine what a wonderful sight it must have been for the ancient people who lived here. It doesn't seem too amazing now in our modern world, but might have been mind-blowing for the prehistoric residents”. Location: Utah. (Photo and caption by Max Seigal/National Geographic Traveler Photo Contest)

Models present Victoria Secret Fantasy Bras priced at $2 million each during a media preview of the Singapore JewelFest in Singapore October 8, 2015. The festival which is in its 13th year, sees over 42 Asian designers participating and over $300 million worth of jewels for sale. It opens from October 9 to 18. (Photo by Edgar Su/Reuters)

Throughout the course of the long war in Afghanistan, Coalition troops have relied on thousands of military working dogs to help keep them safe, and make their jobs easier. The dogs are trained to detect explosives, to find illegal drugs, to search for missing comrades, or target enemy combatants. Not only are they active on the front lines, but behind the lines they serve as therapy dogs, service dogs, and loyal companions. They also share the same risks as the ground troops, suffering injuries and sometimes death on the battlefields. Gathered here are images of these dogs and their handlers in Afghanistan and back home, from over the past several years, part of the ongoing series here on Afghanistan.

Pope John Paul II (1920–2005) is shot by would-be assassin Mehmet Ali Agca in St Peter's Square, 13th May 1981. His attendants help him into his white jeep after the incident. (Photo by Keystone/Hulton Archive/Getty Images)

“Misty Morning”. Every morning, people expect sunny weather. Photo location: Bali, Indonesia. (Photo and caption by Henry Adam/National Geographic Photo Contest)