The whole region of Pieria's Olympus was declared archaeological and historical site for the preservation of its monumental and historical character. Five km away from the sea is Dion, sacred city of the ancient Macedons, dedicated to Zeus and the Twelve Olympians. Its prosperity lasted from the 5th century BC to the 5th century AD. The excavations, continuing since 1928, have revealed numerous findings of the Macedonian, the Hellenistic and the Roman period. Currently there is a unique archaeological park of 200 hectares, with the ancient town and the sacred places of worship, outside its walls. Many statues and other invaluable items are kept in the nearby Dion's archaeological museum. Pimblia and Leivithra, two other towns in Olympus' region, are related to Orpheus and the Orphic mysteries. According to a tradition Orpheus, son of Apollo and Calliope (one of the Muses), taught here the mystic ceremonies of worship of Dionysus (also known as Bacchus). By the sea, in a strategic position, at Macedonia's gates is located Platamon Castle, built between 7th and 10th century AD in the ancient town of Heracleia. To the north the ancient Pydna is located. Here, in 168 BC, the decisive battle between the Macedonians and the Romans took place. Between Pydna and Mount Olympus are a fortified bishop's seat from the Byzantine period called Louloudies and the Macedonian Tombs of Katerini and Korinos.