The Theromopylae was a small passage between the Kallidromo and the Malian Gulf which was very important in Antiquity: it was the only passage from the gulf to Central Greece. Today, there are sable deposits and the passage is a lot wider. The namThermopylae points to the fact that at the location there are hot springs, with very sulfuric water.
Herodotus writes, that the passage was very narrow, and that at its narrowest point it was only about 15 metres (49 ft) wide, which would allow one carriage to pass. During Ancient Greek history, many battles were fought at the location. The most famous is probably the Battle of Thermopylae, which was fought in 480 BC.