Guanabara

Guanabara Bay, or Baía de Guanabara, is a large bay in the southeast of Brazil that forms the natural harbor at the eastern end of the city of Rio de Janeiro. The bay opens to the Atlantic Ocean through a narrow channel near the city and is bordered by several municipalities, including Rio de Janeiro and Niterói. The surrounding landscape features prominent urban and natural landmarks, such as Sugarloaf Mountain and the hills that frame the bay.

Historically, Guanabara Bay has long served as a central harbor for commerce, defense, and urban development. Its location helped establish Rio de Janeiro as a major port and later as the nation's capital for much of the 19th and 20th centuries. The name Guanabara is of Tupi origin, and the bay remains a defining symbol of the metropolitan region, intersecting with transportation, industry, and tourism.

Environmental and planning issues have been prominent in discussions of Guanabara Bay. The area has faced pollution from sewage, industrial discharges, and urban runoff, affecting water quality and marine life. Cleanup and monitoring programs have been implemented by state and municipal authorities, with varying degrees of success over the years. The bay has also served as a venue for major events, including sailing competitions during the Rio de Janeiro 2016 Summer Olympics, which drew attention to water quality and environmental management in the area.

Guanabara can also refer to the former state of Guanabara (1960–1975), a political entity created around the city of Rio de Janeiro and later reintegrated into the state of Rio de Janeiro.