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 15-year-old girl denied a horse from her parents has turned to a cow to fulfil her riding dreams. Teenager Regina Mayer, from southern Germany, is able to ride her cow, Luna. She has even trained her bovine pet to soar over a beer-crate hurdle like a regular show jumper. Why, you may well ask, when most cow-owners are surely content to let the creatures chew and lactate and sit down to indicate the imminent arrival of rain? Well, Regina's parents wouldn't let her have a horse.

These rare photos capture the Flight Deck (cockpit) of the Space Shuttle Endeavour, fully powered for one of the final times. Just a few weeks later, at 9:58am EDT on May 11, Endeavour was powered down for the final time in history. It was the last of the three space shuttles to have power. Below, other views show the mid-deck, gutted of its lockers and storage areas, and three final photos show the white room entrance in the Orbiter Processing Facility, signed by thousands over the years.

Lady officers of the Philippine National Police force show the taped muzzle of their guns at a police camp in Taguig City, south of Manila, Philippines, 22 December 2014. Law enforcement units all over the country held a ceremonial taping of firearms as a counter measure against cases of indiscriminate firing and illegal discharge of service weapons during the upcoming Christmas and New Year celebrations. (Photo by Francis R. Malasig/EPA)

Greyhounds compete during a race at Santiago city, March 8, 2014. With over 100 years of history, greyhound racing attracts people mainly from rural areas of Santiago every weekend. Some dogs come from Argentina, the United States and Ireland and can develop a speed of up to 80 kilometers per hour on a straight running track of about 200 meters, according to organisers. Bets range from $2 to $1,000 per race, offering a livelihood for breeders and gamblers. (Photo by Ivan Alvarado/Reuters)

Japan is a country full of art. Much of this is housed in museums and galleries, but others are right under our feet. We speak, of Japan’s peculiar obsession with manhole covers. Almost anywhere in the country you can find manhole covers with spectacular grounds, each more beautiful and complex than the previous. In recent years, S. Morita photographer has traveled around Japan and leave us this great gathering on the beautiful and artistic Japanese manhole covers.

German pensioner Volker Kraft decorates an apple tree with Easter eggs in the garden of his summerhouse, in the eastern German town of Saalfeld, March 19, 2014. Each year since 1965 Volker and his wife Christa spend up to two weeks decorating the tree with their collection of 10,000 colourful hand-painted Easter eggs in time for Easter celebrations. (Photo by Fabrizio Bensch/Reuters)

People enjoy the fine weather on the coast at Wembury during the first ever nationwide survey to map the location of the threatened and creatures on March 24, 2011 in near Plymouth, England. Often found on the coast, and particularly in the south west of England, the number of oil beetle species found in the UK has halved in the last 100 years and the survey will help establish the whereabouts of the remaining four species and boost efforts to secure their future. The survey is being launched today by Buglife: The Invertebrate Trust and the National Trust in partnership with Natural England and Oxford University Museum of Natural History. (Photo by Matt Cardy/Getty Images)