The pass of Thermopylae ('The Hot Gates') - location of the ancient battle during the Second Greco-Persian War. In this battle the Spartan king Leonid I with small squad resisted against huge Persian army of Xerxes for three days. The Greeks stood up to the last and lost almost everything.
During the battle, the sea is conveniently situated close to the mountains, leaving only a narrow passage. Now the sea receded and there is highway Athens-Thessaloniki.