The Panagia district — the old city on the promontory — is the essential part of Kavala. The Byzantine castle at its tip has commanding views of the bay and the island of Thassos, and the lanes beneath it are lined with Ottoman-era houses and the impressive domed bulk of the Imaret. The Kamares aqueduct, which carried water into the old city from the 16th century, spans the road into Panagia and is one of the best-preserved Ottoman aqueducts in Greece. The house of Mehmet Ali, the Albanian-born founder of modern Egypt's ruling dynasty, is open to visitors in the old quarter. The Archaeological Museum has strong finds from Philippi and ancient Neapolis. Ancient Philippi, 15 km west, is the most important day excursion: the site of a major battle of the Roman civil wars and the first Christian community in Europe.