The Amazon Rubber Boom (Portuguese: Ciclo da borracha [ˈsiklu dɐ buˈʁaʃɐ]; Spanish: Fiebre del caucho [ˈfje.βɾe ðɛl ˈkau̯.ʧo], 1879 to 1912) was an important part of the economic and social history of Brazil and Amazonian regions of neighboring countries, being related to the extraction and commercialization of rubber. Centered in the Amazon Basin, the boom resulted in a large expansion of European colonization in the area, attracting immigrant workers, generating wealth, causing cultural and social transformations, and wreaking havoc upon indigenous societies. It encouraged the growth of cities such as Manaus and Belém, capitals within the respective Brazilian states of Amazonas and Pará, among many other cities throughout the region like Itacoatiara, Rio Branco, Eirunepé, Marabá, Cruzeir