The S-75 (Russian: ?-75; NATO reporting name SA-2 Guideline) is a Soviet-designed, high-altitude air defence system. It is built around a surface-to-air missile with command guidance. Following its first deployment in 1957 it became one of the most widely deployed air defence systems in history. It scored the first destruction of an enemy aircraft by a surface-to-air missile, with the shooting down of a Taiwanese Martin RB-57D Canberra over China on 7 October 1959 that was hit by a salvo of three V-750 (1D) missiles at an altitude of 20 km (65,600 ft) This success was credited to Chinese fighter aircraft at the time to keep the S-75 program secret.