Lyubomir Sergeev Bulgarian photographer Lyubomir Sergeev combines creepy contradictions in his masterfully composed shots.

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.

Toyota driver Rainer Wissmans of Germany drives during the 2nd stage of the Dakar Rally 2015, from Villa Carlos Paz to San Juan January 5, 2015. (Photo by Jean-Paul Pelissier/Reuters)

A model presents a creation from the Fyodor Golan catwalk show at London Fashion Week Autumn/Winter 16 in London, Britain February 19, 2016. (Photo by Neil Hall/Reuters)

Hostesses pose for pictures outside the Great Hall of the People before a meeting ahead of Saturday's opening ceremony of the National People's Congress (NPC), in Beijing, China March 4, 2016. (Photo by Jason Lee/Reuters)

A jockey drives a buffalo in the annual water buffalo race, part of a week-long festival in homage to the animals and in celebration of the rice harvest in Chonburi, Thailand on April 1, 2016. (Photo by Vichaya Pop/Barcroft Media)

A reveller from Unidos da Tijuca samba school performs during the second night of the carnival parade at the Sambadrome in Rio de Janeiro, Brazil, February 28, 2017. (Photo by Ricardo Moraes/Reuters)