Here are a couple of pictures of Bell Tower of Cordoba. This bell tower was built over the ruins of a Muslim minaret in 1660. When the Mesquita got Christianized, the minaret got converted to Bell Tower of Cathedral of Cordoba. For centuries when it was under the control of Muslims a cleric would ride up the ramp of minaret to call out to resident Muslims to face the direction of Mecca and pray. Today
you have to buy tickets to climb up to the top and the reward is fine views of the city.
During the tragic Lisbon earthquake this tower was badly damaged. After enormous repair works like building additional walls the old minaret got hidden. Unfortunately for me I ran out of time, so missed climbing the steep steps to top.