Fortaleza de São João, located in the Urca neighborhood overlooking Guanabara Bay, stands as a 16th-century star fort erected by Estácio de Sá in 1565 to protect Rio de Janeiro from French colonial incursions. The fortress occupies a strategic position between the hills of Cara de Cão and Pão de Açúcar, marking the historic site where the city of Rio de Janeiro was founded. It comprises three smaller redoubts (batteries) and the main Forte São José, completed in 1578 and recognized as the third oldest fort in Brazil. The compound demonstrates sophisticated military engineering adapted to its coastal terrain. Today it functions as the headquarters of the Army's Physical Capacity Training Center and welcomes visitors Tuesday through Sunday, requiring 48 hours advance scheduling for guided tours.
