Men are sent down into the sludge to clear the sewers in the Bangladeshi capital Dhaka on May 23, 2018. The people who do the work aren’t even given any protective clothing or goggles and have to dig out the clogged-up muck with a stick or their bare hands. (Photo by Rehman Asad/Barcroft Media)

Two hippopotamus are fed with pumpkins at the Hanoi Zoo, in Hanoi, Vietnam, 25 October 2018. The zoo has been the home for more than 800 animals of over 90 different species, including three hippopotamus, since it was built in 1976. (Photo by Luong Thai Linh/EPA/EFE)

Germany, Business couple making love under desk. (Photo by Roman Maerzinger/Getty Images)

In advance of Fleet Week performances, U.S. Navy Blue Angels fly above San Francisco with Team Oracle aerobatics pilots Sean D. Tucker and Jessy Panzer on Thursday, October 10, 2019. (Photo by Noah Berger/AP Photo)

An Indian resident assists a dog as he wades through floodwaters in Ahmedabad on July 30, 2014. Rains lashed Ahmedabad and many regions of India's western Gujarat state, wth the Indian Metrological Department warning of heavy rains for the next 48 hours. (Photo by Sam Panthaky/AFP Photo)

A reveler wearing sheepfur costume is seen in front of a bonfire on which they burn a coffin symbolizing winter during the closing ceremony of the traditional carnival parade in Mohacs, 189 kms south of Budapest, Hungary, 07 February 2016. The carnival parade of people, the so-called busos, dressed in such costumes and frightening wooden masks, using various noisy wooden rattlers is traditionally held on the seventh weekend before Easter to drive away winter, and is a revival of a legend, which says that ethnic Croats ambushed the Osmanli Turkish troops, who escaped in panic seeing the terrifying figures during the Turkish occupation of Hungary. (Photo by Tamas Soki/EPA)

Breath at sunset, captures a sea turtle at a dive site called Black Rock. Kāʻanapali, Hawaiʻi, August 2013. (Photo by Christopher Doherty/Smithsonian.com)

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.