(DOG PICTURES/ANIMAL HEROES) Amid the chaos of the September 11, 2001 terrorist attacks, nearly 100 search and rescue dogs were deployed by the Federal Emergency Management Agency (FEMA) to help find survivors at the World Trade Center and Pentagon sites. See the poignant photos of these four-legged 9/11 heroes and their stories below. What heroic faces! — Global Animal

These loyal dogs worked tirelessly to search for anyone trapped in the rubble, alongside countless emergency service workers and members of the public.

Earlier this year, Dutch photographer Charlotte Dumas located 15 of these heroes and has commemorated them in a touching series of portraits entitled “Retrieved.” Traveling to 12 different states in the U.S., Charlotte photographed the surviving rescue dogs, all well into their golden years, at their homes where they still live with their caretakers a full decade after serving their country during its desperate time of need. Their stories are now compiled in the book “Retrieved,” published in September 2011 for the tenth anniversary of the attacks.

Noted for her touching portraits of animals, especially dogs, Charlotte wanted “Retrieved” to serve as recognition for some of the 4-legged first responders.

“I felt this was a turning point, especially for the dogs, who although are not forgotten, are not as prominent as the human stories involved,” explained Charlotte.