In the early, angst-filled days of the Cold War, miners starting carving the insides out of a hill between Dallas and Austin, Texas. The workers didn't know what they were building, but — at 7000 acres — it was huge. At that point in time, it was only known as "Project 76".
This secret underground base was the US Army's only nuclear weapons storage facility called Killeen Base, and it remains an active training facility. After construction started in 1947, US Army engineers carved tunnels out of the solid rock hillside; these became 6m wide corridors with 9m ceilings. It was all reinforced with concrete and sealed off with heavy steel doors. They even installed steel rails in various rooms to accommodate overhead cranes.
Because it was just one of seven atomic weapons storage facilities in the United States, Killeen Base was specifically located so that it would be too far inland for a quick hit by Soviet ground forces.
Of course, during its heyday at the height of the Cold War, there was no shortage of paranoia. Guards could pop up on the surface at any hour of the day or night. Once, they even captured two deer hunters who had been wandering around the land above the underground base because they were suspected of being Communist spies.
A US Army engineer climbs through a confined space in the West Fort Hood underground facility.
It's hard to tell how anyone — even the Communists — would have known the base was there. First of all, it was built into a hillside, like a supervillain's evil lair. It was also never spoken of, leading the locals to come up with all sorts of rumours about what the Army was really doing down there. Some said the underground base actually housed a tunnel that ran all the way to the Gulf of Mexico. Others said it was an underground super-airport where planes could land — though there was already an air field built nearby that could handle planes as big as Boeing B-52s.
That air field stayed open when the underground base closed and the nukes moved out in 1969. At that point in time, the base's super-secret status was lifted, and it became known simply as West Fort Hood. Since that time, the underground base has become home to various training and test missions, primarily for the Mobile Army Sensor System Test and Evaluation Review System (MASSTERS). This unit was established during the Vietnam conflict to test new electronic equipment for the US Army, namely these new-fangled devices called night vision goggles.
Today, West Fort Hood still plays a similar role in the US Army. It's used to train special units in underground combat: a dark and difficult way to fight, simulating what combat might be like inside, say, the caves of Afghanistan. The troops have upgraded from simple night vision goggles to using robots for help with reconnaissance.
Combat engineers take cover behind a "blast blanket" as explosives blow the entry way to the West Fort Hood underground facility.
"As far as we know, Ironhawk Troop is the only unit to have conducted this type of training," said Capt Jarrin Jackson, commander of the Ironhawk Troop in the Third Cavalry Regiment. "Right now there is no field manual or anything to show how to isolate, secure and clear an underground facility like the one at West Fort Hood."
And, based on images from a training mission last year, there's nothing normal about training in a place like West Fort Hood. Then again, that's always been the point.