Cidade Velha — the Old City — is the promontory between the Guamá River and Guajará Bay where Portuguese colonizers built their first fort in 1616. The neighborhood has retained more of its colonial and 19th-century fabric than most Brazilian cities: tile-fronted sobrado houses, narrow streets, churches, and the waterfront market that has operated continuously for four centuries.
The sights are close together and walkable. Start at Forte do Presépio on the western tip, walk along the waterfront past the Cathedral to Ver-o-Peso, then cut back through the streets to Estação das Docas. Allow two to three hours for a relaxed pace. The streets can be very hot in the middle of the day; early morning or late afternoon is more comfortable.
Parts of Cidade Velha are rundown, and some blocks feel neglected. That is part of what makes it interesting — it is not a polished heritage zone but a living neighborhood where people buy fish, hang laundry, and argue in the street.