Slaves were the main source of labour in the coffee plantations until then. As a consequence of this law, and following governmental stimulus towards the increase of immigration, the province began to receive a large number of immigrants, largely Italians, Japanese and Portuguese peasants, many of whom settled in the capital. The region's first industries also began to emerge, providing jobs to the newcomers, especially those who had to learn Portuguese. By the time Brazil became a republic on November 15, 1889, coffee exports were still an important part of São Paulo's economy. São Paulo grew strong in the national political scene, taking turns with the also rich state of Minas Gerais in electing Brazilian presidents, an alliance that became known as "coffee and milk", given that Minas Gerais was famous for its dairy produce. During this period, São Paulo went from regional center to national metropolis, becoming industrialized and reaching its first million inhabitants in 1928. Its greatest growth in this period was relative in the 1890s when it doubled its population. The height of the coffee period is represented by the construction of the second Estação da Luz (the present building) at the end of the 19th century and by the Paulista Avenue in 1900, where they built many mansions. Industrialization was the economic cycle that followed the coffee plantation model. By the hands of some industrious families, including many immigrants of Italian and Jewish origin, factories began to arise and São Paulo became known for its smoky, foggy air. The cultural scene followed modernist and naturalist tendencies in fashion at the beginning of the 20th century. Some examples of notable modernist artists are poets Mário de Andrade and Oswald de Andrade, artists Anita Malfatti, Tarsila do Amaral and Lasar Segall, and sculptor Victor Brecheret. The Modern Art Week of 1922 that took place at the Theatro Municipal was an event marked by avant-garde ideas and works of art. In 1929, São Paulo won its first skyscraper, the Martinelli Building. The modifications made in the city by Antônio da Silva Prado, Baron of Duprat and Washington Luiz, who governed from 1899 to 1919, contributed to the climate Development of the city; Some scholars consider that the entire city was demolished and rebuilt at that time. São Paulo's main economic activities derive from the services industry – factories are since long gone, and in came financial services institutions, law firms, consulting firms.