Santa Trinita di Saccargia
A Pisan Romanesque cathedral about 15 km from Sassari on the road toward Olbia, built in 1116. The story goes that a local judge's wife was visited by the Virgin Mary here, who told her she was pregnant. The church is in excellent condition — a striking black-and-white striped campanile rising from flat scrubland — and well worth the detour.
Castelsardo
About 35 km northeast, Castelsardo is a beautifully preserved medieval hill town with a 12th-century Doria castle, good views over the Gulf of Asinara, and a museum dedicated to the local basket-weaving tradition.
Porto Torres and the Sarcapos Ruins
25 km northwest on the coast. Porto Torres is primarily a ferry port, but the Basilica di San Gavino (late 11th century) is one of the most important Romanesque churches in Sardinia, and the archaeological remains of the Roman town of Turris Libisonis are worth a look.