The last surviving search-and-rescue dog from the 9/11 attacks took her last walk this week, past teary-eyed firefighters, police, and other first-responders who saluted her with a "Wall of Honor."

Handler Denise Corliss led her longtime partner, named Bretagne, a Golden Retriever two months shy of her 17th birthday, into a veterinary office. Bretange's old-age and failing kidneys had led Corliss to the painful decision of having her humanely euthanized.

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The 9/11 attack on the World Trade Center was Bretagne's (pronounced "Brittany") first deployment with Corliss. They would searched for survivors in dozens of other disasters over the years, including Hurricanes Katrina and Rita.

Last year, Bretagne was thrust back into the spotlight, when she and Corliss were flown to New York City for a night on the town, honoring her as the last of the 9/11 "hero dogs."

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A half-hour after Bretagne walked into the vet's office, the first-responders again snapped to attention and saluted as her body was carried past the wall of honor, draped in the Texas flag.

"To the over 400 members of the Cy-Fair Volunteer Fire Department, Bretagne was a civil servant, a hero and is family," the Department said in a statement. "We will remember her fondly, and continue serving the community with her as inspiration."

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Even in death, Bretagne will continue to serve. After a lifetime of service, she still has one last mission to complete. Her autopsy will provide doctors with clues about her ability to remain resilient into old age against pollutants from the 9/11 attacks that have left hundreds of people with cancers and other health problems.

(WATCH the video below from Inside Edition) — Photo: Cy-Fair Volunteer Fire Department

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