and the anthropic areas. In the urban area of Marabá, the anthropic forests predominate. Because of its diverse nature, the municipality holds one of the largest natural heritage sites in Brazil, housing large forest reserves such as the Tapirapé Biological Reserve, with 103,000 ha (1,030 km²), and the Tapirapé-Aquiri National Forest with 190,000 hectares ha (1,900 km²), in addition to the Mãe Maria Indigenous Land, with 64,488,416 ha (644.88 km²), which is close to the municipal seat of Marabá, belonging to the municipality of Bom Jesus do Tocantins. Marabá is located in a low altitude area in the connexion of two rivers - Itacaiúnas and Tocantins - and suffers from annual floods due to the topography and direct influence of four rivers: Itacaiunas, Tocantins, Tauarizinho and Sororó. In addition to the basins related to these rivers, the municipality is inserted in the basins of the rivers Aquiri, Tapirape, Gray, Black, Parauapebas and Red. Of these, the basins of the Tapirapé, Cinzento and Preto rivers are included totally in the area of the municipality. The basin of Itacaiúnas stands out for bathing the whole municipality, in whose mouth is the municipal headquarters of Marabá and covers the largest area, that is, 5,383.4 km². Economy The municipality of Maraba experienced various economic cycles. Until the early 1980s economy was based on the extraction plant. At first revolved around the extraction of latex rubber, whose lucrative attracted large numbers of the Northeast. Since the late nineteenth century (1892) until the late 1940s, was marked by the extraction of the rubber boom that has contributed greatly to the economy of the city and the region, however, the rubber crisis led the council to a new cycle . This time, the cycle of Brazil nuts, which for years led the municipal economy. There was also the cycle of diamonds between 1920 and 1940, which were mainly found on the river Tocantins. With the discovery of Serra Pelada Maraba went through cycles of mining mostly the extraction of gold. Since the early 1970s installation of the Grande Carajás project and steel industries diversified and boosted the local economy. Primary sector Today, Maraba is the economic center and a vast administrative region of the Amazon agricultural frontier ", the city has one of the most significant economic growth in the country. Livestock based on cattle ranching is an activity of great importance for the municipality, and ensure