Developed and made in the Soviet Union, the SA-2 has been used more widely than any other air defense missile in the world. In the Soviet Union it was called the Dvina; in the West it was known by its NATO code name, SA-2 Guideline (SA meaning surface-to-air). The SA-2 became operational in 1959 and was acquired by all Soviet client states. In 1960 an SA-2 downed the American U-2 spy plane piloted by Francis Gary Powers.