Between Macedon and the southern states of Greece was a range of lofty and almost impassable mountains. These mountains extended through the whole interior of the country, and the main route leading into southern Greece passed around to the eastward of them, where they terminated in cliffs, leaving a narrow passage between the cliffs and the sea. This pass was called the Pass of Thermopylæ, and it was considered the key to Greece. There was a town named Anthela near the pass, on the outward side.