The Fortaleza de São Gabriel is a historic fort located on the island of São Gabriel da Cachoeira in Brazil. Built in the 18th century, it was designed to protect the region from foreign invasions and to assert Portuguese sovereignty in the Amazon. The fort features thick stone walls and strategic positioning overlooking the river. Today, the fort is a significant cultural and historical site, attracting visitors interested in Brazilian history and colonial architecture. It is part of the Amazon rainforest ecosystem, showcasing the unique blend of natural beauty and historical significance in the region.