Castle of Sant Blai Monument · Tivissa, Ribera d'Ebre, Tarragona On the summit of the Coll del Ventall, above the hermitage of Sant Blai, in the municipality of Tivissa, remains survive of walls belonging to an Arab castle declared a cultural asset of national interest; only the base still stands, made of irregular stone bonded with mortar. Documented as a castell termenat (boundary castle) in 1174, it commands a wide view over Prades, Siurana, the Priorat and the Ribera d'Ebre, from Garcia to Miravet, as well as over the Terra Alta. According to the British Arabist Peter Scales, the tower's first floor had a rectangular plan of 9 by 5 metres, with a wall two metres thick. Photo: Angela Llop (CC BY-SA 2.0) What to see and do in Tivissa