Capo San Marco, Mediterranean promontory in Cabras, Sardinia.

Capo San Marco is a broad, low promontory of brown and green vegetation at the southern end of the Sinis Peninsula, closing the Gulf of Oristano to the north. A cylindrical light-brown stone tower with a slightly wider base and flat top stands near the crest, and a pale dirt path runs past it toward the right. The lower slopes meet the sea in rocky shores and small sandy inlets with scattered grey boulders.

The promontory lay beside the ancient Phoenician city of Tharros, which remained inhabited until the 11th century. Its position provided natural protection for this early coastal settlement.

The name San Marco comes from the saint, and the cape closes the Gulf of Oristano to the north. Near the parking area the last reed fisherman's hut still stood in 2008; the village itself was rebuilt in masonry during the last century. The lighthouse and surrounding area served as a filming location for Rocco Papaleo's film Una piccola impresa meridionale.

Access is via a walking path from San Giovanni di Sinis village, where parking is available nearby. Wear sturdy shoes and bring water, as the terrain is exposed and sunny.

In the seagrass beds of the Mare Morto, on the sheltered eastern side, the bivalve Pinna nobilis, known locally as nacchera, can be seen just a few metres from the shore. On the open-sea side, rocks close to the coast hold schools of damselfish fry, colourful blennies, sea bream, white seabream and the occasional scorpionfish.