1 RAF Menwith Hill

United Kingdom
RAF Menwith Hill is a British military base that contains an extensive ground satellite station and is a communications intercept site and missile warning point. It has been described as the largest electronic surveillance station in the world. It is supposed to be an element of ECHELON, a system supposedly created to monitor the military and diplomatic communications of the Soviet Union and its Eastern Bloc allies during the Cold War in the 1960s. All this mystery makes it the number 1 of most secret and inaccessible places in the world.