Jose Goncalves
CC BY-SA
Also known more simply as Vila do Conde Castle, Forte de São João (Baptista) was first constructed in the 1570s. Standing at the mouth of the River Ave, it is named in honour of Saint John the Baptist, the city's patron saint. However, it was originally named for the Virgin Mary.
Built in order to protect this important trading port from attack, the fort comprises five individual bastions, facing coast, river, and inland too. It would once have been akin to a small village, complete with its own water source, chapel, kitchens, dungeons and weapons store, so that it could survive a siege. Today much of this history has been lost, although its ancient walls can now be enjoyed as part of a variety of special events, while dining at the restaurant, or when staying the night in the boutique hotel that occupies part of the structure.