I'm at Berlin's Teufelsberg Field Station, a former listening post for the US National Security Agency , known for its giant white bubbles on top of the facility that look like a collection of moons.

In West Berlin, a tower topped with a giant “golf ball” sits incongruously at the summit of a heavily wooded hill. The tower is part of Field Station Berlin – an abandoned, Cold War era spy ...

Testing throughout West Berlin revealed Teufelsberg, a manmade hill in the Grunewald forest, had ideal conditions for such a center. In 1963, the Americans built Field Station Berlin atop the hill.

On the second-highest hill in Berlin sits the carved-out remnants of Field Station Berlin Teufelsberg, a former NSA spy station used to collect signals intelligence on Soviet-aligned East Germany ...

Devil's Mountain in the Grunewald (Green forest) is an artificial hill built upon the rubble of all the Berlin buildings that were bombed in World War II. The field station expanded rapidly ...