Watch final goodbye of last surviving 9/11 Ground Zero rescue dog

Bretagne, the last surviving Sept. 11 rescue dog that spent days searching through the rubble at Ground Zero, has crossed over the Rainbow Bridge.

The 16-year-old golden retriever was put down on Monday at a veterinary clinic in Houston. According to BuzzFeed, she had been having difficulties walking for the past few years and was also suffering from kidney failure.

Bretagne — pronounced Brittany — was deployed a week after the 2001 terrorist attacks when she was just 2 years old. She was joined by her handler Denise Corliss and was part of the search and rescue team Texas Task Force 1, BuzzFeed reported.

Together with Corliss, Bretagne worked 12-hour shifts for 10 days searching the scene for any human remains, according to ABC7 New York.

In the year prior to the attacks, the beloved pup became one of the founding canine members of the Cy-Fair Volunteer Fire Department’s K9 Search and Rescue Team in Texas.

Along with responding to the World Trade Center, Bretagne also responded to other disasters such as Hurricanes Katrina and Rita.

The golden retriever retired from active duty when she turned 10 years old, but continued to serve as an ambassador for the volunteer fire department’s public events and also helped search dogs in training.

Bretagne also would regularly visit elementary school students and special needs students.

“Her calm demeanor and warm heart helped the young and old through their own difficult moments,” the Cy-Fair Volunteer Fire Department said in astatement on Facebook.

On Monday, the fire department organized a final farewell for Bretagne with volunteers saluting her as she made her way into the vet.

“Some may say that the most a dog could be is a pet, however, to the over 400 members of the Cy-Fair Volunteer Fire Department, Bretagne was a civil servant, a hero and is family,” the statement said. “We will remember her fondly, and continue serving the community with her as inspiration.”