A stuffed rabbit doll sits among children's beds standing in the abandoned kindergarten of Kopachi village located inside the Chernobyl Exclusion Zone on September 29, 2015 near Chornobyl, Ukraine. Kopachi, a village that before 1986 had a population of 1,114, lies only a few kilometers south of the former Chernobyl nuclear power plant, where in 1986 workers inadvertantly caused reactor number four to explode, creating the worst nuclear accident in history. (Photo by Sean Gallup/Getty Images)

Spanish actor Antonio Banderas embraces a robot used in the film Automata during a photocall on the third day of the 62nd San Sebastian Film Festival, September 21, 2014. Banderas stars in and produced the science fiction film, which is part of the festival's official section. (Photo by Vincent West/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.

Passengers brave the strong winds as they wait for a bus, in Hong Kong, Monday, September 15, 2014. The Hong Kong Observatory issued the number 8 southeast storm signal, as Typhoon Kalmaegi edges closer to Hong Kong. (Photo by Kin Cheung/AP Photo)

Irina, worker of a petrol station, now member of reconnaissance team of pro-Russian rebels' in the town of Makievka, eastern Ukraine, October 6, 2014. Like the men in the conflict, the women come from all walks of life. Some women come to serve with their husbands and boyfriends, others are single. Female fighters on both sides said the men in their units treat them as equals, though sometimes showing more leniency. They have little respect for men who have not taken up arms. On both sides the fighters expect a long conflict, despite the fragile ceasefire now in place. (Photo by Shamil Zhumatov/Reuters)

A hot air balloon floats over farm fields south of Washington, Ill., as the sun slips behind clouds on the autumn afternoon of Wednesday, September 24, 2014. (Photo by Ron Johnson/AP Photo/Peoria Journal Star)

Young Slovaks dressed in traditional costumes throw a bucket of water at a girl as part of Easter celebrations in the village of Trencianska Tepla, Slovakia, April 9, 2012. Slovakia's men splash women with water to symbolize youth, strength and beauty for the upcoming spring season. (Photo by Samuel Kubani/AFP)

Among the fish populations that could be harmed by the Xayaburi dam in Laos is the critically endangered Mekong giant catfish, considered by the Guinness Book of World Records to be the world’s largest freshwater fish. The fish, which grows to 650 pounds and about 10 feet long, is only found in the Mekong River. It is migratory, moving between downstream habitats in Cambodia upstream to northern Thailand and Laos each year to spawn. Some experts fear the Xayaburi dam could block the migration and drive the giant catfish to extinction. (Photo by Courtesy of Zeb Hogan/University of Nevada, Reno)