ECHELON, originally a secret government code name, is a surveillance program (signals intelligence (SigInt) collection and analysis network) operated by the United States with the aid of four other signatory states to the UKUSA Security Agreement (Australia, Canada, New Zealand, and the United Kingdom), collectively known as the Five Eyes.
The ECHELON program was created in the late 1960s to monitor the military and diplomatic communications of the Soviet Union and its Eastern Bloc allies during the Cold War, and it was formally established in 1971.
By the end of the 20th century, the system referred to as ECHELON had evolved beyond its military and diplomatic origins into "a global system for the interception of private and commercial communications" (mass surveillance and industrial espionage).