Watchtower of Arrebatacapas Monument · Torrelaguna, Sierra Norte, Madrid A Muslim watchtower at the Arrebatacapas pass, in the municipality of Torrelaguna, one of the six watchtowers of the Jarama that formed the Muslim communications network for the protection of Toledo. It was built in the late 9th or 10th century, under the emirate of Muhammad I or the caliphate of Abd al-Rahman III, as part of the watchtower system of the Middle March of al-Andalus, which watched over the passes of Somosierra, Navacerrada, Fuenfría and Alto del León towards the Manzanares valley. It is a cylindrical structure of masonry and mortar, 19 metres in perimeter and originally 12 or 13 metres high, with its only entrance 2.5 metres above the ground and an interior divided into three floors. Today it is partly in ruins and has been protected as a Bien de Interés Cultural (Spain's highest level of heritage protection) since 1985. Photo: Rowanwindwhistler (CC BY-SA 3.0) What to see and do in Torrelaguna