A pink elephant balloon, one of the entries in the Canadian Hot Air Balloon Championships, lands in a field in High River September 27, 2013. The event is a qualifier for the World Hot Air Balloon Championships in Sao Paulo in 2014. (Photo by Mike Sturk/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.

Competitors take part in the 8th annual World Gravy Wrestling Championships at the Rose n Bowl Pub in Bacup, north west England on August 31, 2015. Contestants must participate in fancy dress and wrestle in a pool of Lancashire Gravy for 2 minutes whilst being scored for a variety of wrestling moves. (Photo by Oli Scarff/AFP Photo)

Two biplanes of the Team Breitling cross during a training flight prior the AIR14 air show in Payerne, Switzerland, August 29, 2014. (Photo by Peter Schneider/EPA)

Satarupa Chakraborty, 5, dressed as a Kumari, yawns while she is worshipped by a Hindu priest during the religious festival of Durga Puja in Agartala October 2, 2014. (Photo by Jayanta Dey/Reuters)

Cuban girls dressed as nurses and a lizard wait for their turn to dance during a visit by the Gay Men's Chorus of Washington in Havana July 13, 2015. The choir made its first appearance on July 12, 2015 in Cuba as part of a tour that will include a dozen concerts in the context of the restoration of relations between the island and the United States. (Photo by Enrique de la Osa/Reuters)

Soldiers take part in a drill during a heavy snow in Heihe, Heilongjiang province, February 26, 2014. (Photo by Reuters/China Daily)

The 100-metre (300-foot), sword-wielding statue of “The Motherland” is seen in the National Museum of the History of the Great Patriotic War in Kiev March 17, 2014. On a blustery day on the banks of the Dnieper, the statue of “The Motherland”, a Soviet hammer and sickle on her shield, towered overhead, a reminder of the common cause Ukrainians and Russians died for side by side in their millions in World War Two and which Russian President Vladimir Putin thinks Ukraine has betrayed by turning to “fascism” and the West. (Photo by Konstantin Grishin/Reuters)