Cabo Frio is a municipality in the Brazilian state of Rio de Janeiro. Its beaches include central Praia das Dunas and Praia do Forte, both known for their strong surf. Praia das Conchas has calmer waters. Passagem, the city’s oldest area, features colonial buildings and the Capela de São Benedito, a 1701-built church. Overlooking the sea is 17th-century São Mateus fort, with its rusted cannons.