Guanabara Bay is located in southeastern Brazil, in the state of Rio de Janeiro. It is the second largest bay in Brazil (after the Bay of All Saints), has an area of 412 square kilometers, length - 31 kilometers, width - 28 kilometers. The cities of Rio de Janeiro and Duci di Caxias are located on the west coast of Guanabara, and Niterói and San Gonzalo on the east. More than 30 rivers flow into the bay, about 130 islands are located in it, including the Governor's Island and Financial Island. On the coast of Guanabara, despite urbanization, preserved areas of pristine nature with tropical and mangrove forests, there are many beaches and recreation areas. In the language of the Tupi Indians (the indigenous population of Brazil), the name of the Gulf of Guanabara means "bosom of the sea" or "bosom of the sea", the tribes of Tamoio and Tupiniquim, who lived on its shores, were engaged in fishing, hunting and farming. The Gulf was opened by the Europeans on January 1, 1502, the Portuguese mariners Gaspar de Lemos and Gonzalo Coelho (captains of the caravel as part of an expedition to the coast of Brazil under the command of Pedro Cabral) share the honor of its discovery. Initially, the Portuguese took the 1.5-kilometer strait connecting the bay with the Atlantic Ocean over the river, and gave it the name January River (Rio de Janeiro), later the settlement based on the coast of Guanabara Bay will also receive this name, and then the capital of Brazil (until 1960). In 1536, the forts of Santa Cruz, São João, Lajes, and Villaleganyon were erected by the Portuguese on the shores of the bay, which made the bay almost impregnable for an attack from the ocean. At the entrance to the bay is located Sugar Loaf Mountain, which rises 396 meters above sea level, to enjoy stunning views of the bay from its top, you can use the cable car built in 1912. In 1974, between the cities of Rio de Janeiro and Niteróa, through the Gulf of Guanabara, the Rio Niterói bridge was built, whose length is more than 13 kilometers and the height is 72 meters, which allows large vessels to pass unhindered under it. Unfortunately, human activities have caused enormous damage to the ecosystems of the bay - wastewater, industrial waste, deforestation and several large-scale oil spills have led to a significant reduction in the number of fish, other marine animals and birds living in the Guanabara Bay, mangrove forests were also threatened with complete destruction. . In preparation for the 2016 Summer Olympic Games in Brazil, the Rio de Janeiro authorities, international and environmental organizations are taking measures to decontaminate water and clean up the waters and coasts of Guanabara Bay.