On 25 April 1952, the other two parts of the former German states of Baden and Württemberg, South Baden and Württemberg-Hohenzollern merged and formed the modern German state of Baden-Württemberg, with Stuttgart as its capital. Since the 1950s, Stuttgart has been the third largest city in southern Germany behind Frankfurt and Munich. The city's population, halved by the Second World War, began sudden growth with the mass influx of German refugees expelled from their homes and communities by the Soviets from the late 1940s until 1950 to the city. Economic migrants, called ""Gastarbeiter"," from Italy, and later Greece and Turkey but primarily from Yugoslavia, came flocking to Stuttgart because of the economic wonder called the ""Wirtschaftswunder"" unfolding in West Germany. These factors saw the city reach its (then) peak population of 640,000 in 1962.