Torre di Longonsardo, Military tower and museum in Santa Teresa Gallura, Italy.

Torre di Longonsardo is a truncated-cone tower with a circular base 19 m in diameter, built entirely of granite and standing 11 m high on the promontory between the bays of Santa Reparata and Porto Longone. Its only entrance is 6 m above ground, reached by a metal staircase added during World War II in place of rope ladders. Inside, a circular hall 10 m across has a stone basin by the southeast wall and a dome vault on a central pillar; a spiral stair leads to the roof terrace, where two cannons once stood.

Construction began in 1577 under orders from Spanish King Philip II to defend against Barbary pirate raids. It became part of a larger network of defensive structures protecting settlements along the Sardinian coast.

The tower is also called Torre di Santa Teresa, after the saint to whom the nearby town is dedicated. Each June, the town recalls the 1802 anti-Savoy uprising when the priest Francesco Sanna Corda was killed at the foot of the tower.

The tower stands on the promontory between the bays of Santa Reparata and Porto Longone. The only entrance is 6 m up, reached by a metal staircase added during World War II in place of the old rope ladders. Inside, a spiral staircase leads to the terrace where two cannons once stood.

The tower includes an original rainwater collection system that reveals how inhabitants managed water in this remote location. The remains of this system are still visible today and show the practical ingenuity of the period.