It is probably Gallura’s largest tower, most likely the most imposing one ever built on the island by the Spanish crown and is the symbol of Santa Teresa Gallura, together with the beach over which it watches. The Longonsardo tower stands on a promontory to the north-east of the town of Gallura, not far from where a castle once stood in the Middle Ages. It has a diameter of 19 metres at the base, some 16 in the upper cylindrical body, and a height of 11 metres. The building material used was, of course, granite, perhaps taken from the ruins of the manor. The tower was classified as de armas, or 'strong', built to house a garrison and heavy defence weapons.

It started appearing in documents in 1577, when it had become necessary to defend the harbour from attacks by Barbary pirates and the tower was built as part of a defensive strategy developed by King Filippo II, who instituted the “Royal administration of towers.” A surrounding wall was added, of which you can still see some remains, as well as a cistern for collecting rainwater. The entrance is six meters from the paved interior and will lead you to the fortified area, a domed room with a central pillar. On the right you’ll find the stairs that led to the parade ground.