The town's medieval pillory, the Pelourinho, stands at the heart of the old quarter — a twisted Manueline column erected in 1515 when King Manuel I elevated Arcos to village status. The Baroque Church of Nossa Senhora da Lapa, completed in 1767 to a design by André Soares, is considered one of the finest examples of his work in the Minho. The older Church of São Bento, attached to a former Franciscan monastery (1674), is quieter and less visited.
The main reason most people pass through Arcos is access to the Peneda-Gerês National Park, Portugal's only national park, which begins at the edge of the municipality. The park office in town can provide maps and trail information.