COLO SPRINGS, Co. - Driving past Cheyenne Mountain, it's easy to overlook what really exists inside this mountain, how it was built in the 50's and 60's, or what purpose it serves today.
Although many who grew up in the Colorado Springs area visited Cheyenne Mountain Air Force Station with their scout troops or elementary classes, tours of the complex ended around the time of the September 11 attacks, so only very few are able to get inside the mountain these days.
KRDO Newschannel 13 was recently granted access to Cheyenne Mountain Air Force Station, the first time a local television station has gone beyond the blast doors in years.
Everyone allowed in had to submit to an extensive background check, and any camera equipment brought inside had to be pre-approved by the military.
Colonel Gary Cornn Jr., Commander of the 721st Mission Support Group at CMAFS, was the guide.
Following a security briefing, Cornn walked us down the half mile tunnel to the blast doors.
It's an experience that he says never gets old.
"You never get tired of walking into an iconic facility like this," he says.
The first thing that crosses your mind in the tunnel is how little it has changed sinced the early 1960's when it was carefully carved out by an army of workers using dynamite.
An estimated 23,000 truckloads of granite were hauled from the mountain during the blasting.
The Cheyenne Mountain facility was built to resist a nuclear blast, in response to the Cold War arms race.
Accordingly, the blast doors are not at the end of the tunnel, but around a corner.
"The tunnel is built from north to south, it's open so that the force of the blast goes all the way through the tunnel, and the complex was built offset from that, so that the blast goes right by," explains Col. Cornn.
Each of the two original blast doors weighs 25 tons, with 22 pins to lock them in place.
They are guarded by airmen with M-4 rifles.
During the Cold War, one door was always closed as a precaution.
Today, both are allowed to remain open.
The last time both were closed was in the hours after the attacks on September 11, 2001, when the extent of the attack was still uncertain.
Beyond the doors are the 15 buildings, each standing two to three stories.
They are carefully balanced on thousand-pound springs.
The majority of the 1300 springs are the original pieces put in place back in the 60's.
None of the buildings are allowed to touch the mountain itself.
"So if there was seismic activity, either natural or caused by a blast, they would move independently," explains Col. Cornn.
Survivability, however, is not the only asset of Cheyenne Mountain.
Features that allow sustainability are just as critical.
It was built to house the most critical government operations for an extended period even after the blast doors close.
There are four underground reservoirs.
One is filled with freshwater for human consumption.
Two are filled with nonpotable water intended for industrial cooling.
The final reservoir is filled with diesel to power the six generators that can kick on to provide backup power to the complex.
The military would not release the amount of time the diesel would supply the complex, nor would they say how much food is on hand for those caught inside during a secure period.
Upstairs from the generators is the room that controls power, water, and air flow.
There are very flew computer monitors in the room.
Most of the controls were put in place around the time the generators were last replaced, 1976.
There is also a fitness center to keep any attack survivors healthy, a small chapel, and a convenience store for the personnel assigned to the mountain.
Some have questioned whether Cheyenne Mountain AFS would be able to stand up to a modern day nuclear blast the same way it would stand up to a 1950's era blast.
"I don't know," says Col. Cornn.
He said that with a smile, because that's really not his concern.
The mission of the 721st is to secure and operate the mountain, making sure it can still collect data from sensors and satellites around the globe to monitor any and all types of pending attacks, and making sure the mountain is ready for the worst day in American history.
"That's a mission that's been here forever, and that's a mission that will continue in the future, and that's why Cheyenne Mountain is here," said Col. Cornn.
Cornn admitted that the government considered closing Cheyenne Mountain about 10 years ago, but the emerging threat of a nuclear attack from rogue nations like Iran and North Korea has created new value.
Specifically, the threat of a powerful electronmagnetic pulse from a nuclear detonation in space has brought a number of new groups seeking EMP protection to Cheyenne Mountain.
Find out more about this emerging threat and the impact on the mountain in Part 2 of our special report on Friday at 10:00.