Story highlights Bretagne, one of the last living 9/11 search and rescue dogs, trained at Disaster City

The College Station, Texas, facility is a realistic classroom for search and rescue teams

Hundreds of dogs have and dog handlers have received FEMA certification there

Dogs must have special traits to succeed at search and rescue

Search-and-rescue dog handler Denise Corliss loves Disaster City.

That's what the Texas A&M Engineering Extension Service calls its 52-acre search and rescue training center in College Station, Texas. Disaster City is a classroom for chaos -- a manufactured jungle of concrete, rebar and other rubble you might find in the aftermath of a hurricane or explosion or the 9/11 attacks.

"It's like a playground for first responders," says Corliss, a member of the Texas Task Force 1 urban search and rescue team. "It's like my second home."

Search and rescue teams travel to the facility from around the nation to receive training certified by the Federal Emergency Management Administration. Most of the trainees are human. Some are dogs. Hundreds of FEMA canine teams have trained at Disaster City.

For 15 years, Corliss has spent two weekends a month at the center working with dogs. That includes her golden retriever, Bretagne, one of the last surviving 9/11 search and rescue dogs.

Dogs and their handlers climb up and down the piles of concrete, hiding objects for canines to find. Trainers teach and test the dogs to hone their smelling and searching skills by sending them down into simulated tornado shelters and up into second story buildings.

Photos: Photos: 'Somebody's Gotta Do It' Photos: Photos: 'Somebody's Gotta Do It' Folks who 'gotta do it' every day – Mike Rowe, host of CNN's "Somebody's Gotta Do It," gets rescued by Texas A&M paramedics during a training exercise. Click through the gallery for more images of folks who #GottaDoIt and watch CNN in 2015 for Season 2. Hide Caption 1 of 20 Photos: Photos: 'Somebody's Gotta Do It' Folks who 'gotta do it' every day – The firefighters at Texas A&M show Rowe how to properly put out a fire. Hide Caption 2 of 20 Photos: Photos: 'Somebody's Gotta Do It' Folks who 'gotta do it' every day – Darby Kittel shows Rowe the recycled parts he uses to build tiny houses. Hide Caption 3 of 20 Photos: Photos: 'Somebody's Gotta Do It' Folks who 'gotta do it' every day – Ariane Daguin teaches Rowe about the feeding process they use on the farm. Hide Caption 4 of 20 Photos: Photos: 'Somebody's Gotta Do It' Folks who 'gotta do it' every day – Joel Martin and Ariane Daguin show Rowe how to properly handle the chicks. Hide Caption 5 of 20 Photos: Photos: 'Somebody's Gotta Do It' Folks who 'gotta do it' every day – Rowe tries on one of the head pieces backstage at Pageant of the Masters. Hide Caption 6 of 20 Photos: Photos: 'Somebody's Gotta Do It' Folks who 'gotta do it' every day – Rowe sits in front of one of the life-sized paintings created for Pageant of the Masters. Hide Caption 7 of 20 Photos: Photos: 'Somebody's Gotta Do It' Folks who 'gotta do it' every day – Rowe spits a seed during the Watermelon Thump competition in Texas. Hide Caption 8 of 20 Photos: Photos: 'Somebody's Gotta Do It' Folks who 'gotta do it' every day – Rowe visited a survival school, where Thomas Coyne gave him a spear-throwing lesson. Hide Caption 9 of 20 Photos: Photos: 'Somebody's Gotta Do It' Folks who 'gotta do it' every day – Rowe tries to start a fire during his survival school experience. Hide Caption 10 of 20 Photos: Photos: 'Somebody's Gotta Do It' Folks who 'gotta do it' every day – Rowe learns the signature "Marching Cobra" move from drum team leader Don Daughtry. Hide Caption 11 of 20 Photos: Photos: 'Somebody's Gotta Do It' Folks who 'gotta do it' every day – Daughtry and Lionell Hamilton show Rowe a little drum technique. Hide Caption 12 of 20 Photos: Photos: 'Somebody's Gotta Do It' Folks who 'gotta do it' every day – Employees teach Mike Rowe about the "oyster orgy." Hide Caption 13 of 20 Photos: Photos: 'Somebody's Gotta Do It' Folks who 'gotta do it' every day – Rowe traveled to a Maryland facility that's helping to replenish the endangered whooping crane population. Armed with crane puppets and special clothing, he joined the workers who interact with the birds. Hide Caption 14 of 20 Photos: Photos: 'Somebody's Gotta Do It' Folks who 'gotta do it' everyday – Native only to North America, just 22 whooping cranes existed on the planet in 1922, the facility's Dr. John French told Mike. Today there are more than 500. Hide Caption 15 of 20 Photos: Photos: 'Somebody's Gotta Do It' Folks who 'gotta do it' every day – Evan Voyles shows Rowe the sign he made for "Lucy's Fried Chicken." Volyes runs "The Neon Jungle," a sign making business in Austin, Texas. Hide Caption 16 of 20 Photos: Photos: 'Somebody's Gotta Do It' Folks who 'gotta do it' every day – Rowe holds performer Chelsea Bakken above the pool at the Las Vegas water acrobatic show "Le Reve." Hide Caption 17 of 20 Photos: Photos: 'Somebody's Gotta Do It' Folks who 'gotta do it' every day – "Le Reve" wardrobe technician Maria Palacios Togni has touched up about 132,000 shoes over the past nine years. Hide Caption 18 of 20 Photos: Photos: 'Somebody's Gotta Do It' Folks who 'gotta do it' every day – Rowe talks with Leila Cohoon at her hair art museum in Missouri. "Leila's Hair Museum" displays more than 600 wreaths and 2,000 pieces of jewelry made from human hair. The practice was popular in the Victorian era. Hide Caption 19 of 20 Photos: Photos: 'Somebody's Gotta Do It' Folks who 'gotta do it' every day – Join Mike for his CNN Original Series, "Somebody's Gotta Do It," which focuses on people whose passion for their jobs compels them to do it without question. It's when "your love for it pushes you right down the road," Rowe said. "Those are the people you want to know." Hide Caption 20 of 20

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Back in 2001, Corliss and Bretagne (pronounced, "Britney") were fresh graduates of Disaster City when they were deployed to New York shortly after the World Trade Center attacks.

Corliss joined hundreds of other search and rescue teams sent from around the world to find survivors at ground zero, working 12 hours a day for two weeks straight.

We know now there were very few survivors found in the rubble of the twin towers, and Bretagne, like so many other searchers, worked hard -- only to find none.

But Corliss discovered something unexpected: rescuers and firefighters would approach Bretagne and pet her. Soon they'd be sharing their personal stories with Corliss, describing the missing friends, loved ones and colleagues they were searching for. Bretagne had become a kind of therapy dog. "Dogs can be so comforting, so it makes sense to me now," she says. "I just didn't anticipate that, then."

9/11 was only the first of many national disasters that called Bretagne and Corliss into action.

Deployments followed for Hurricanes Katrina, Rita and other storms. Once Corliss watched Bretagne risk her own safety when the dog found herself standing on the end of a dangling staircase.

"She walked to the edge of it and she stopped -- turned -- and she came back down," Corliss recalls. "She did exactly what she was supposed to do, but it scared me a bit."

Despite all that training, Corliss admits "there were still times when I held my breath and said, 'I hope she does this right. I hope she's OK.' "

Pushy puppy

It's no coincidence that search and rescue dogs such as Bretagne succeed while working under such dangerous conditions.

From the time they're puppies, dogs must survive a rigid screening process before they can do this kind of work.

When Corliss spotted Bretagne, she had a feeling this dog might be right. The puppy was pushy.

Sharing a plastic kennel with eight other puppies, Bretagne buffaloed her way through the pack from back to front, to greet Corliss.

"That kind of pushy behavior helped her be the persistent don't-give-up-style of working dog that I needed later," says Corliss.

A few other qualities Corliss says are key to good search and rescue dogs:

-- High toy drive: "Their toy is their paycheck. We're looking for the dog that's going to be so over-the-top crazy for their toy that they're going to be happy going over this rubble pile."

-- High prey drive: "They've got to be persistent. They're going to hunt for survivors, and continue to hunt, and not give up."

-- Nerve strength: "We need dogs that are not going to be scared to climb a ladder up to the second story of a building -- alone without a handler — or to go down into a dark tunnel."

-- Focus: "The dog can't be concerned about a nearby jackhammer or loud truck or crane or emergency sirens."

Bretagne left Texas Task Force 1 in 2009 to focus on her work as a local fire department search and rescue dog. Then after a couple more years, it was time for her to retire altogether. But that didn't mean the end of Bretagne's public service.

Now 15, Bretagne spends time once a week teaching kids how to read. Really.

She visits elementary school classrooms, where children, who "may be intimidated or uncomfortable reading out loud to their classmates, have an opportunity to develop reading skills by reading to her," Corliss says.

Corliss has raised and trained two other golden retriever search and rescue dogs: Aid'N, now 10 and retired, and Taser, age 3.

Taser will continue the legacy that Aid'N and Bretagne have carried, dedicating their lives to helping people survive calamity.

Flying drones and other robotic technology provide new options for search and rescue teams, but Corliss says dogs will always be a part of the toolbox, along with cameras and listening devices.

"I don't think there will ever be a substitute for their agility and sense of smell," she says. "In that way, they're better than any other tool that we have out there."