We find several remains from the Spanish Civil War all over the Minorcan coastline. Sanitja harbour and the Cap de Cavalleria are no exception. The Republican army was scattered throughout the island in small artillery and infantry units and garrisons, guarding the most important bays. Their objective was to defend the island from the potential danger of an amphibious invasion from Majorca .

There are many smaller fortified points buried and very well camouflaged whose aim was to protect any beach from their pillboxes with machineguns and rifles, such as the two that can be seen in the Cavalleria beach, one on each of the beach ends. There is another one on the east side of Cala Viola overlooking Fornells bay, and another one at the mouth of Sanitja harbour. Also, even today we can see what is left of the coastal trenches between Sanitja harbour and Cala Viola.

During the Civil War, old weaponry was recovered from the depots of La Mola fortress. It was obsolete due to its short range and slow firing speed, but still good to basically defend several coastal points in Menorca .

Fixed artillery positions were built in the Cap de Cavalleria to install 4 15-mm Krupp steel canons. At the present time we only see 4 circular features excavated in the rock west to the lighthouse. Near the lighthouse quarry there is a tunnel that was used as an ammunition depot.