Visitors wear shirts with an image of former Chinese leader Mao Zedong at the Shanghai World Expo site in Shanghai, May 2, 2010. (Photo by Aly Song/Reuters)

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.

In this handout artists impression provided by the Russia 2018 Organising Commitee, the Rostov on Don Stadium is shown as proposed and presented as part of the Russia 2018 World Cup bid, on September 29, 2011 in Russia. (Illustration by Russia 2018 via Getty Images)

Actress Michelle Rodriguez attends the Shane Black 9th annual Hallowen party held on October 31, 2003 in Hancock Park, Los Angeles. (Photo by Frazer Harrison/Getty Images)

Couples take part in a Valentine's Day attempt to break the record for the world's largest simultaneous gay kiss on February 14, 2004 in Rome, Italy. (Photo by Franco Origlia/Getty Images)

“Amy Jade Winehouse (14 September 1983 – 23 July 2011) was a British singer-songwriter known for her powerful contralto vocals and her eclectic mix of musical genres including R&B, soul and jazz. ... Winehouse died at the age of 27 on 23 July 2011 at her home in London; police have said that the cause of her death was «as yet unexplained»”. – Wikipedia

Photo: Amy Winehouse vigil outside Amy Winehouse's North London home on July 23, 2011 in London, England. Singer Winehouse, 27, was found dead today. (Photo by Sylvia Linares/Getty Images)