Castle of Montoliu Monument · la Riera de Gaià, Tarragonès, Tarragona Also called the castell de Santa Margarida or "el Castellot", it stands near the mouth of the Gaià; it belonged to the Claramunt family from when Ramon Berenguer I granted it to them in 1060, with the Montoliu family as castellans, among whom the vice admiral Berenguer de Montoliu stood out. A well-preserved 11th-12th-century circular tower and a two-story rectangular body with a pointed vault, added in the 13th or 14th century, survive, along with a rock-cut moat. It suffered severe deterioration after the Peninsular War. A Bien Cultural de Interés Nacional (Catalonia's top heritage-protection category). Photo: joan ggk (CC BY 2.0) What to see and do in la Riera de Gaià