Piraeus is the third-largest city in Greece and its most important harbour. The area was first settled – according to the Hippodamian system of town planning – in the time of Themistocles, when the Long Walls (478 BC) were built, and it became especially important when Athens emerged as a naval power. Ancient Piraeus had two harbours, Zea and Munichia, the latter now known as Mikrolimano or Tourkolimano. Above Mikrolimano stands Castella hill, with pretty neighbourhoods and a chapel Prophet Elijah on its top. Two ancient theatres have come to light in Piraeus, along with traces of the ancient fortifications. The most important finds from the area can be seen in the city’s Archaeological Museum; among them are three bronze statues of Apollo (530 BC), Athena (4th century BC), and Artemis (4th century BC). Also of interest is the Nautical Museum, showing the maritime history of Greece from antiquity down to the present day.