Teufelsberg (German for Devil's Mountain) is a man-made hill in Berlin, Germany, in the Grunewald locality of former West Berlin. It rises about 80 metres (260 ft) above the surrounding Teltow plateau and 120.1 metres (394 ft) above the sea level. The hill is made of rubble, and covers an under-construction Nazi military-technical college (Wehrtechnische Fakultät). During the Cold War, there was a U.S. listening station on the hill, Field Station Berlin, and run by the NSA (National Secuirity Agency). It was built in 1963 and lasted until the fall of the Berlin Wall