About 10 km southeast of Castelsardo, the church of Nostra Signora di Tergu stands almost alone in the Anglona hills — the surviving remnant of a Benedictine monastery founded in 1113. The architecture is Romanesque, built in alternating bands of dark basalt and pale limestone in the distinctive style of medieval Sardinian churches influenced by Pisan builders.
The monastery buildings are long gone, leaving the church in solitary occupation of a flat terrace above the surrounding farmland. It is rarely visited and open irregularly, but the exterior alone — particularly the facade and the apse — makes the short detour worthwhile for anyone interested in Sardinian medieval architecture. The drive through the Anglona hills on small roads also gives a good sense of the agricultural landscape of the interior.