The Cathedral was restored in the 1930s turning the former Baroque façade into a Medieval Pisan style façade, more akin to the original appearance of the church. The bell tower is original. The interior has a nave and two aisles, with a pulpit (1159-1162) sculpted for the Cathedral of Pisa but later donated to Cagliari. The crypt houses the remains of martyrs found in the Basilica of San Saturno.

The Basilica of San Saturno is one of the most important Palaeo-Christian monuments in Sardinia. Dedicated to the martyr killed under Diocletian's reign, it was built in the 5th century. Of the original building the central part remain and the dome, to which two armes (one with a nave and two aisles) was added. A Palaeo-Christian crpyt is also under the church of San Lucifero (1660). This has a Baroque façade with ancient columns and sculpted parts, some of which found in the nearby necropolis.

A testimony of the Roman domination is the Roman Amphitheatre, carved into a block of rock (the typical lime-stone on which Cagliari is built). The Amphitheatre still stages open-air operas and concerts during the summer.

his rich collection of objects and other artifacts contains many high quality pieces. The succession of the island's ancient cultures is reconstructed through the exhibition of ceramics and pre-nuragic statuettes, copper ingots, nuragic bronzes and ceramics, inscriptions, Phoenician tomb furnishings and ceramics, inscribed headstones (one of the world's most important collections), and splendid Punic jewelry. Rich ceramics, terra-cotta, glass objects, statues, Roman sarcophagi, and gold jewelry dating from the High Medieval period, as well as artifacts from the Tuvixeddu and Pula necropolises (objects produced by the Phoenicians, or imported from Greece, Italy, and Spain) are particularly interesting.