It used to be an American SAS (Special Ammunition Site).
These facilities were used to store, guard and service different types of nuclear weapons. In this facility, among others, W-52-warheads for MGM-29 Seargant short-range ballistic missiles were stored.
The site was built in 1960 and was guarded in two "rings", of which the outer ring alone was guarded by a batallion of soldiers.
When the American troops left in late 1991, they didn't leave much, obviusly. The buildings have been left, but with no interior left whatsoever.
But the area combined with its history sure makes for a very interesting trip and a great photo location!
Part 1 | Part 2