An opposition supporter gestures with a knife during clashes with police in Kibera slum in Nairobi, Kenya on October 26, 2017. Kenyans trickled into polling stations today for a repeat election that has polarised the nation, amid sporadic clashes as supporters of opposition leader ignored his call to stay away and tried to block voting. (Photo by Goran Tomasevic/Reuters)

Four-month-old fox cubs squaring up to each other in Walthamstow, England on August 7, 2015. (Photo by Greg Morgan/Barcroft Media)

Bet: Oshane Grant, 42, of Easton, Bristol, was expecting to pocket £9,250 if France, Serbia and Argentina's football teams all scored at least three goals in their World Cup 2014 qualifiers (dailymail).

A model prepares backstage ahead of the Amber & Thomas show during Rosemount Australian Fashion Week Spring/Summer 2011/12 at Overseas Passenger Terminal on May 3, 2011 in Sydney, Australia. (Photo by Ryan Pierse/Getty Images)

An activist of the anti-G8 forum “Block G8” shows his middle finger to a police helicopter passing overhead June 07, 2007 at Bollhagen, near Heiligendamm, Germany. (Photo by Carsten Koall/Getty Images)

During his time in Ethiopia, New York-based art director and photographer Diego Arroyo spent time with the Hamar, Mursi, Dassanech, and Arbore Tribes. They, along with several others tribes, make up the 200,000 people situated in Africa’s Great Rift Valley. The people of the Omo Valley are still primarily herders and farmers, living an isolated and simple life. While they have yet to be truly touched by globalization, they could soon disappear. Their way of life is being threatened by a massive hydroelectric dam. (Photo by Diego Arroyo)

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.

A girl struggles with winds from approaching Typhoon Matmo along the eastern coast of Keelung, northeastern Taiwan, Tuesday, July 22, 2014. (Photo by Wally Santana/AP Photo)