An Arab tower with a roughly square floor plan. After the reconquest of Cáceres in 1170 by Ferdinand II of León, a family member established the Congregatio de Cáceres in the city, which would later be known as the Order of the Knights of Santiago. The name of the tower derives from Caliph Abu Ya'qub, whose troops conquered the city in 1173. This tower was the defensive bastion of the knights of the Order until they were defeated by a siege. During the 16th and 18th centuries it was known as the Clock Tower. It is now open to the public. It houses the Three Cultures Visitor Centre. Spectacular views from the top.