Spanish Tower of San Giovanni is named after the nearby church of San Giovanni di Sinis. It was built between the late 15th and early 16th centuries on top of the hill overlooking the archaeological area of Tharros, offering a wide view over the Gulf of Oristano and the open sea. It is one of the most imposing towers in the gulf, second only to Torre Grande.

The tower was supposedly built on the remains of a single-tower nuraghe and a Punic tower, using stones repurposed from the city of Tharros. It consists of two superimposed cylindrical structures with a base diameter of fourteen meters and a total height of fifteen meters. The entrance is about eight meters above ground, accessible today via an external staircase built in the 19th century. A large circular domed room, illuminated from above through a skylight, has a hatch in the floor that allowed access to the rainwater cistern. The room also features a fireplace and a powder magazine. On the terrace, accessible by an internal staircase, two accommodations were built in the second half of the 19th century when the tower was garrisoned to suppress smuggling. The tower was armed with cannons and swivel guns and manned by a garrison consisting of a captain (alcaide), an artilleryman, and four soldiers.

The building was restored between 1987 and 1990.

The complex of coastal towers in Sardinia has represented one of the island’s main defensive systems for centuries. These watchtowers and defensive towers were largely built under Spanish rule, but also in the preceding period, using similar materials and construction techniques. They were placed in strategic locations that allowed for spotting potential enemies coming from the sea, from Saracen pirates (7th-15th century) to Barbary corsairs (16th-19th century), particularly after the fall of Constantinople in 1453 and the expulsion of the Moors from Spain in 1492.

In 1587, King Philip II of Spain established the “Royal Administration of the Towers”, entrusting it with the task of building new towers, managing them, recruiting soldiers, and supplying them with weapons.

The towers were placed in strategic points allowing to monitor wide stretches of sea, and each tower was positioned so it could communicate with nearby towers using light signals.

San Giovanni Tower, Torre Vecchia (or San Marco Tower), and the Sevo Tower (Turr’e Seu) were built along the Sinis coastline between the 16th and 17th centuries, initiated by the Spanish Crown to protect the local populations from pirate and Barbary corsair raids coming from North Africa. Another tower, Su Pottu, was probably established at the end of the 17th century on the shore of the Cabras lagoon to guard and protect the fishing activities in the lacustrine basin.

Torre Vecchia (or San Marco Tower)

Torre Vecchia (“old tower”), or San Marco Tower, is located along the eastern coast of Capo San Marco.
It has a truncated conical shape, with a base diameter of about seven meters and a height of about nine meters. The tower was accessed directly from the terrace via a rope or ladder, which could be easily removed by the guards in case of danger.

The tower is built with sandstone blocks and originally featured walls plastered with lime mortar.</span

Sevo Tower (Turr’e Seu)

In the natural oasis of Seu, which is part of the Sinis Marine Protected Area, perched over the sea stands the Sevo Tower, a fortress erected by the Spanish Crown in the late 16th century.

It has a truncated conical shape, with a base diameter of more than seven meters and a height of almost ten meters. The entrance is about four meters above the ground and leads to a domed room. To the left, a staircase ascends to the terrace, where cannons were placed on the parapet.

From the tower, one can admire a breathtaking panorama, especially at sunset. To the right, the coastline with the three “jewels” of Sinis: the beaches of Maimoni, Is Arutas, and Mari Ermi, characterized by their colorful quartz grains. To the left, the view follows the coastline ending at Capo San Marco.