The selfie is the most popular photography trend of the internet today. It's gotten so popular, in fact, that even our beloved feline friends have started to catch on. I dare you to keep the smile off your face for this one!

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 model backstage during day 1 of Aspen Fashion Week 2011 on March 13, 2011 in Aspen, Colorado.

Italian blogger and fashion designer Chiara Ferragni poses as she arrives for the amfAR charity dinner during the fashion week in Milan, Italy, Thursday, September 21, 2017. (Photo by Antonio Calanni/AP Photo)

Nicki Minaj attends the 14th Annual CFDA Vogue Fashion Fund Gala at Weylin on Monday, November 6, 2017, in New York. (Photo by Splash News and Pictures)

Danielle Sellers attends The Beauty Awards at Tower of London on November 28, 2017 in London, England. (Photo by Lia Toby/WENN)

A masked participant carries a burning matress during the ancient carnival of Zubieta, in the northern Spanish Navarra province on January 30, 2018. The yearly three day festivities, revolving mainly around agriculture and principally sheep hearding, run on the last Sunday, Monday and Tuesday of January where Navarra Valley locals from two villages dress up and participate in a variety of activites as they perform a pilgrimage through each village. (Photo by Ander Gillenea/AFP Photo)