from a second-tier industrial city to a world-class city. Thus, Detroit earned its famous nickname, the Motor City. At the turn of the 20th century, no one industry was dominant in Detroit. Early automotive production, which was still a relatively small industry at the time, is evidenced by structures such as the Ford Piquette Avenue Plant (1904) (a National Historic Landmark), and multiple structures in the surrounding Piquette Avenue Industrial Historic District (including the now-destroyed E-M-F/Studebaker Plant, 1906) and the New Amsterdam Historic District (including the original Cadillac factory, 1905) and small factories such as the Crescent Brass and Pin Company Building (1905). Then as automobile assembly and associated manufacturing came to dominate Detroit over the next thirty years, the newly minted automotive magnates built commercial and office buildings such as General Motors Building (1919), the General Motors Research Laboratory (1928), and the Fisher Building (1928). In 1914, Ford revolutionized labor relations when he announced he would pay workers in his plants five dollars a day— about double the going rate at rival firms. In addition to attracting the best workers in Detroit, Ford's high wage policy effectively stopped the massive turnover rate, raised productivity, lowered overall labor costs and helped to propel the Model T to industry dominance. By the 1920s, however, Ford's formula of cheap cars with few options fell behind General Motors, which emphasized upscale quality and variety, and provided financing for car buyers. Labor relations in the automobile industry transformed again in 1935 when the United Auto Workers labor union was founded in Detroit. The rapid growth of the automobile industry led to rising demands for labor. Immigrants from Europe initially filled much of the labor demand, but restrictive immigration acts in 1921 and 1924 caused a dramatic reduction in the supply of foreign-born workers to the United States. Meanwhile, the automobile industry was growing exponentially. Beginning during World War I, Ford began hiring African Americans to close the labor shortage. At this time, the hardships of life in the Jim Crow South and the promise of manufacturing jobs in the North brought African Americans to Detroit in large numbers in the Great Migration. This massive influx of workers and their families caused Detroit's population to soar from 265,000 to 1.5 million between 1900 and 1930 and pushed the city's boundaries outward. The population boom led to a severe housing shortage and the construction of public