The Calahorra tower (Torre de la Calahorra) is a fortified gate in the historic centre of Córdoba. The edifice is of Islamic origin. It was first erected by the Almohad Caliphate to protect the nearby Roman Bridge on the Guadalquivir. The tower, standing on the left bank of the river, originally consisted of an arched gate between two. A third tower was added to the existing ones, in the shape of two cylinder connecting them.
References:Herceg Novi was founded (on a former small fishing village, existing since Roman Empire times) as a fortress in 1382 by first Bosnian King Stjepan Tvrtko I and was called Sveti Stefan or Castelnuovo. The Turks conquered Herceg Novi in 1482, and ruled for 200 years, until 1687. However, there was a short pause between 1538 and 1539 when it was held by the Spaniards before they were defeated in the Siege of Castelnuovo. Turkey ruled again until 1687, from then until 1797, the town was ruled by the Venetian Republic.
The Herceg Novi old town is amazing. It is on a fairly steep hill that leads all the way down to the sea. Wandering through the small stairways to the various plazas and fortresses is a many hour adventure.