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 Colombian anti-narcotics policeman stands guard after burning a cocaine lab, which police said belongs to criminal gangs, in a rural area of Calamar in Guaviare state, Colombia, August 2, 2016. Colombian law enforcement has destroyed 104 cocaine laboratories capable of producing some 100 tonnes of the drug annually, the head of the anti-narcotics police said on Tuesday. (Photo by John Vizcaino/Reuters)

Edibles are displayed at Shango Cannabis shop on first day of legal recreational marijuana sales beginning at midnight in Portland, Oregon October 1, 2015. The sale of marijuana for recreational use began in Oregon on October 1, 2015 as it joined Washington state and Colorado in allowing the sale of a drug that remains illegal under U.S. federal law. (Photo by Steve Dipaola/Reuters)

Lisandra Perez, 7, practices in his house before his flute lesson at the Integral System of Artistic Education for Social Inclusion (SIFAIS) center in the poor neighborhood of La Carpio, Costa Rica October 8, 2015. SIFAIS center is developing a social program with the help of 156 volunteers who teach art, music, sports and education, for children and youth living in La Carpio, known for being the home to gangs, violence, drugs and social vulnerability, according to the centre. (Photo by Juan Carlos Ulate/Reuters)

Abdulahi Yaroow, 13, smokes a cigarette while chewing khat at the same time in Mogadishu August 10, 2014. Grown on plantations in the highlands of Kenya and Ethiopia, tonnes of khat, or qat, dubbed “the flower of paradise” by its users, are flown daily into Mogadishu airport, to be distributed from there in convoys of lorries to markets across Somalia. Britain, whose large ethnic Somali community sustained a lucrative demand for the leaves, banned khat from July as an illegal drug. This prohibition jolted the khat market, creating a supply glut in Somalia and pushing down prices, to the delight of the many connoisseurs of its amphetamine-like high. (Photo by Thomas Mukoya/Reuters)

A terminally ill patient raises his arm in a hospice for those dying of AIDS at the Buddhist temple Wat Prabat Nampu in Lopburi province, north of Bangkok November 30, 2014. From 1992, the temple has provided housing for HIV positive patients and palliative care for those in the final stages of the AIDS disease. Data from 2013 estimates Thailand has 450,000 people living with HIV/AIDS, but only 353,000 have access to life-saving antiretroviral drugs. (Photo by Damir Sagolj/Reuters)

Hawaii has long been known as a tropical paradise, but in recent years another image has intruded into the state's carefully crafted one of idyllic beaches and relaxing resorts: homelessness. The number of homeless people has grown in recent years, leaving the state with 487 homeless per 100,000 people, the nation's highest rate per capita, above New York and Nevada, according to federal statistics. Many of the homeless, however, defy the stereotype of the mentally ill or drug addicted. They are families, with men and women who work full-time jobs. They are struggling to get a foothold in a place with a high cost of living and low wages. Here: in this Thursday, August 27, 2015 photo, a homeless man drinks water while sitting on the beach at Ala Moana Beach Park located near Waikiki in Honolulu. (Photo by Jae C. Hong/AP Photo)