The pass of Thermopylae separates Mt Kallidromo from the sea of the Malliakos Gulf. One kilometer long and – in antiquity – only 5-20 metres broad, the pass was the scene of many battles down the centuries, the most famous of them being the heroic resistance of the Spartans to the invading Persians in 480 BC. Xerxes, the Persian King, had brought his enormous army west and south through northern Greece, but the Greeks were waiting for him at Thermopylae. The Greek forces resisted bravely, but were betrayed by a certain Ephialtes, who showed the Persians how to outflank the Greeks along a mountain path called the Anopaea. The Spartan general Leonidas now held the battlefield with 300 of his own people and 700 men of Thespiae-all of whom fought to the death, after first killing large numbers of Persians. There is a statue of Leonidas on the battlefield now, to commemorate the heroism of the Spartans.