On the right bank of the River Lima, the Santiago da Barra Fortress was built under Spanish rule during the reign of Philip I of Portugal. It has a polygonal design and the entry to the fortress is through an arched gate. Inside the fortress is the headquarters of Oporto and North of Portugal Tourism, a congress centre and the Viana do Castelo hotel and catering and tourism school. As you leave, just walk a little more to pay a visit to Nossa Senhora da Agonia Church, an 18th-century rococo-style church, with a representation of the Passion of Christ in the interior. Have a good look at the pipe organ, the carving and flowery ornaments, which suggest water in motion. In August, the area around Santiago da Barra Fortress attracts pilgrims from all over the country for the Nossa Senhora da Agonia Pilgrimage. It is considered one of the biggest festivals in Portugal, full of colour, ethno-folk wealth and an unparalleled diversity of typical costumes.