TEUFELSBERG

 Amajor signals intercept station located during the Cold War in the British Sector of Berlin, strategically situated on the summit of a man-made mountain constructed over what was intended to be the Third Reich’s military academy. Bombed into total destruction in 1945, the site was used to dump the rubble from 800,000 buildings, and it proved to be an ideal site for a joint National Security Agency–GCHQ listening post which, by virtue of its isolation from the city, offered an almost ideal electronic environment, free from interference. With its tall aerials, it was able to receive signals from Czechoslovakia and 50 miles into Poland to collect Warsaw Pact traffic. The U.S. Army Security Agency Field Station began operating in 1957, when it was known as the 280th ASA Company, and proved its worth by monitoring the military VHF traffic generated by 600,000 Soviet troops during the Prague crisis of 1968. The number of masts and distinctive golfball antennas increased continuously until 1977, when the site was absorbed into the NSA as the U.S. Air Force’s 6912th Electronic Security Group, with more than a thousand Americans and a hundred British technicians from the RAF’s No. 26 Signal Unit and No. 13 Signal Regiment maintaining 24-hour cover in three shifts on East German and Soviet telephone, telex, and radio circuits.