Nebet Tepe is one of the hills of Plovdiv where the ancient town was founded. The earliest settlements on Nebet Tepe are dated back to 4000 BC. The site was first settled by Thracians, later expanded by Philip II of Macedon and the Roman empire. As the town expanded, Nebet Tepe became the citadel of the town's acropolis. There are remains of the city's walls, towers, and a postern from the time of Justinian leading down to the Maritsa river. Today, the archaeological complex on the hill is one of the most popular tourist sights in Plovdiv and a cultural monument of national significance.