The Amazon rubber cycle, or boom (Ciclo da borracha, ˈsiklu da buˈʁaʃɐ; Fiebre del caucho, ˈfjeβɾe ðel ˈkawtʃo, 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, Cruzeiro do Sul and Altamira; as well as the expansion of Iquitos in Peru, Cobija in Bolivia and Leticia in Colombia. The rubber boom occurred largely between 1879 and 1912. There was heightened rubber production and associated activities again from 1942 to 1945 during the Second World War.
Natural rubber is an elastomer, also known as tree gum, India rubber, and caoutchouc, which comes from the rubber tree in tropical regions. Christopher Columbus was one of the first Europeans to bring news of this odd substance back to Europe, but he was not the only one to report it. Around 1736, a French astronomer recalled how Amerindians used rubber to waterproof shoes and cloaks. He brought several samples of rubber back to France. Rubber was used as an eraser by the British scientist Joseph Priestley, with "rubber" entering English parlance as a substitute for the term "eraser".
It was not until the 1800s that practical uses of rubber were developed and the demand for rubber began. A rubber factory that made rubber garters for women opened in Paris, France, in the year 1803. However, the material still had disadvantages: at room temperature, it was sticky. At higher temperatures, the rubber became softer and stickier, while at lower temperatures it became hard and rigid.