Perdigal Tower, locally known as Torre del Perdigal, lies next to the beach, south west of the village of Retamar in the province of Almería in Spain.
Ever since the Turkish settlement in Algiers in 1516, the entire coast of the Spanish Mediterranean was threatened by attacks of Barbary pirates who landed on the coast and ravaged and looted towns and rural settlements, taking away the inhabitants as slaves. So, in 1552, during the reign of Charles V, the Holy Roman Emperor, lots of defensive watch towers were started being built along the coast, from Alicante down to Cádiz. Most however were built or completed during the reign of his son, Philip II of Spain, during the second half of the 16th century.
Although normally dated to the end of the 16th century, some say that Perdigal Tower could be in origin an Arab tower having been built in the 13th century. This round tower communicated with the city of Almería and the nearby García Tower. If enemy ships were sighted, it communicated with the other towers by means of smoke during daytime and fire during nighttime.
At present Perdigal Tower can freely be visited. I found evidence that the tower was inhabited by a vagabond, so be careful. Just a simple tower.