Facebook CEO Mark Zuckerberg (L) watches a demonstration of the new Facebook video chat during a news conference at Facebook headquarters July 6, 2011 in Palo Alto, California. Zuckerberg announced new features that are coming to Facebook including video chat and a group chat feature. (Photo by Justin Sullivan/Getty Images)

Two children jumping through a water hydrant's shower on a New York street. They have come from a neighbouring co-educational playgroup organised by the city's Police Department. (Photo by Orlando/Getty Images). 1950

Erzhena Zhamyanova (“Amar Sain” theater) and Buryat folk instruments orchestra – Dance Monkey. “Dance Monkey” is a song by Australian singer Tones and I, released on May 10, 2019 as the second single (first in the US) from Tones and I's debut EP The Kids Are Coming.

Triumph International's lingere set of bra and underwear come with a lock attached to the shorts and a key for the woman to give the key to her beloved on November 24, 2004 in Tokyo, Japan. (Photo by Koichi Kamoshida/Getty Images)

When he's driving, New York-based painter Gregory Thielker takes in the views that change from moment to moment: the road, the sky, other cars. “Inside the car it's easy to forget the outside temperature, humidity, the noise of the road”, he says. “But something happens when rain interrupts the view: the lens through which we are seeing is revealed. Water both obscures and highlights the landscape”. Gregory Thielker's exhibition “Between here and now” will be at Castor Gallery in lower Manhattan from early March. Here: “Complete Stop”. (Painting by Gregory Thielker)

A surfer drops in on a large wave at Praia do Norte, in Nazare December 11, 2014. Praia do Norte beach has gained popularity with big wave surfers since Hawaiian surfer Garrett McNamara broke a world record for the largest wave surfed here in 2011. (Photo by Rafael Marchante/Reuters)

Pfc. Sebastian Rodriguez, machine gunner, Weapons Platoon, Lima Company, 3rd Battalion, 3rd Marine Regiment, Marine Rotational Force – Darwin, fires an M240 machine gun during a night squad-attack exercise, here, May 22, 2013. (Photo by Sgt. Sarah Fiocco/U.S. Marines)

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.