The Castillo de Lorca, often called the Fortaleza del Sol, dominates the skyline from a steep hill above the old town. The fortifications date from the Islamic period in their earliest layers and were extensively rebuilt and extended by the Castilians after the reconquest of 1244. Two great towers survive — the Torre Alfonsina and the Torre del Espolón — along with long stretches of curtain wall and a substantial Jewish quarter discovered during recent excavations.
The site is run as a heritage park, with a modern visitor centre, well-designed exhibitions on the three cultures that lived here, and a small synagogue museum inside the medieval foundations. Allow two hours, longer if you take the path all the way back down into the city centre on foot.