Reconnaissance played an important role during the Cold War. Spy planes and satellites of the United States showed that the Soviet Union greatly exaggerated its nuclear arsenal. The reconnaisance programs of both nations allowed them to engage in nuclear arms reduction treaties by enabling them to determine if the other was fulfilling its promises.
The most noteworthy spy plane of the Cold War was the U-2 of the United States. The "Utility Two" was developed by 'Skunk Works' of Lockheed and first tested on August 1, 1955 at Groom Lake, Nevada (a site more commonly known to the public as "Area 51"). From 1956 to 1960, U-2 planes flew twenty-four times over the Soviet Union. On May 1, 1960, a U-2 plane was shot down over Sverdlovsk, Russia by a missile. The Soviet Union protested America's use of spy planes, and this incident revealed the existence of the U-2 to the American public. On October 14, 1960, a U-2 spy plane photographed the first evidence of Soviet installations in Cuba.
The United States Air Force and the CIA began developing the Corona program of satellite reconnaissance in 1958 and was put under the management of the National Reconnaissance Office in 1960. Declassified in 1995, it used high-resolution film to photograph a wide variety of sites in the Soviet Union and China: Moscow, nuclear test sites, missile complexes, shipyards, and gold dredging operations.
The Soviet Union developed its own satellite reconnaissance program called Zenit, which first launched in April 1962. To increase its flight time, its orbit was at a higher altitude than that of the Corona program, although this resulted in lower resolution imagery.