In the Middle Ages – 10th and 11th centuries – the river Gaià (which flows through the country of Tarragona) played a very strategic role, as it acted as a natural border between the county of Barcelona and Al-Andalus. For this reason, nearly fifty castles and some watchtowers were built along the route to stop the Muslim invasion to the north. The castle route of Gaià is easily accessible by car and includes the castles of La Riera de Gaià, Tamarit, Torredembarra, Vespella, Altafulla, El Catllar, Clarà, Creixell, Ferran, La Nou de Gaià, La Pobla de Montornès and Renau. See below link to website with more details.
