Medium tank to manufacture a well-balanced medium tank in very large numbers - around 57,000 T-34s and 49,000 M4 Sherman tanks were built during the war period. During and after World War II, the roles of light tanks were gradually taken over by less-expensive armoured cars and specialised reconnaissance vehicles. Heavy tanks, having shown their limitations in combat, experienced a limited post-war arms race of progressively more heavily armed and armoured designs. With the rise of more sophisticated anti-tank missile weapons, to which heavy tanks had demonstrated high vulnerability, these too were eventually phased out. With advances in technology, aspects such as
US signals intelligence in the Cold War a decade of world change, with changes in Cold War alliances and emphasis, the first submarine attack since World War II in the context of a regional war involving extensive power projection, low- and medium-intensity operations, and continuing national policy development. Roughly from the late 1980s on, there was cooperation between the US and the PRC in collecting SIGINT of mutual interest, principally against Russia. It is believed that the Qitai and Korla sites, in Xinjiang (Sinkiang) are operated jointly by the Chinese and the US CIA Office of SIGINT Operations against Soviet missile tests and space launches, but their