(L-R) Edmea Pereira, 69, Elsa Rodrigues, 61, and Osmidio Conde, 71, take part in their surf class in Santos, Sao Paulo state, Brazil, March 16, 2016. When work is up, surf is up in Brazil, as a group of retired citizens take to the waves in keep-fit, keep-young sessions at a surf school in the city of Santos. The classes are run for free, three times a week at the Cisco Arana school, which aims to prove that age is just a number. (Photo by Nacho Doce/Reuters)

A woman protests her eviction from a building she and others invaded about a week ago in the Flamengo neighborhood of Rio de Janeiro, Brazil, Tuesday, April 14, 2015. Police dislodged squatters from the building slated for use as a luxury hotel for the 2016 Olympics in Rio de Janeiro. (Photo by Silvia Izquierdo/AP Photo)

A Myanmar Shiite Muslim devotee runs barefoot over a bed of burning coals as he takes part in a Muharram procession ahead of the Islamic holiday Ashura, in Yangon, Myanmar, October 22, 2015. Muslims across the world are observing Moharram, the first month of Islamic calender, the climax of Moharram is the Ashura festival commemorating the martyrdom of Imam Hussein, a grandson of the Prophet Mohammed in the Iraqi city of Karbala in the seventh century. (Lynn Bo Bo/EPA)

“The Lun-class ekranoplan (NATO reporting name Duck) was a ground effect vehicle (GEV) designed by Rostislav Evgenievich Alexeev and used by the Soviet and Russian navies from 1987 until sometime in the late 1990s. It “flew” using the lift generated by the ground effect of its large wings when close to the surface of the water – about four metres or less. Although they might look similar and/or have related technical characteristics, ekranoplans like the Lun are not aircraft, seaplanes, hovercraft, or hydrofoils – ground effect is a separate technology altogether. The International Maritime Organization classifies these vehicles as maritime ships. The name Lun comes from the Russian for harrier”. – Wikipedia (Photo by Igor113)

A dog takes a rest under a destroyed house at a site where a landslide swept through a residential area at Asaminami ward in Hiroshima, western Japan, August 20, 2014. At least 36 people, including several children, were killed in Japan on Wednesday, when landslides triggered by torrential rain slammed into the outskirts of the western city of Hiroshima, and the toll could rise further, police said. Seven people were missing after a month's worth of rain fell overnight, loosening slopes already saturated by heavy rain over the past few weeks. (Photo by Toru Hanai/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.

People look at damaged trees after a tornado hit Funing on Thursday, in Yancheng, Jiangsu province, China June 24, 2016. (Photo by Aly Song/Reuters)

A member of a Chinese opera troupe applies make-up before performing at a shrine during the annual vegetarian festival in Bangkok, Thailand, on October 4, 2016. (Photo by Athit Perawongmetha/Reuters)