The Amman Citadel, crowning the hill of Jabal al-Qalaa at the heart of the city, is an ancient site occupied for thousands of years, with remains from the Roman, Byzantine and Umayyad periods. Highlights include the Temple of Hercules, the Umayyad Palace and sweeping views over the old town and the Roman theatre below. Ticketed entry lets visitors explore the ruins and the archaeological museum, making it the most important historic site in the capital.