A wood-and-earth fort -- constructed on the site of today's more substantial installation -- was the very first thing built in Belém when the Portuguese arrived in 1616. The fort was variously abandoned, rebuilt, and renamed over the years (it's also known as the Forte do Castelo and the Forte do Belém). The last major military renovation occurred in the 1850s. In the 1980s the nearly ruined fort was again restored, this time by Brazil's federal caretaker of historic sites. From the ramparts you get a wonderful view of Ver-o-Peso Market, the Catédral da Sé, and the Praça Dom Pedro II. A small museum inside the fort tells the history of the area's indigenous tribes and the settlement of Belém. Allow 30 minutes.