Persian Wars: Battle at Thermopylae.

The pass at Thermopylae was a superb place to withstand an attack. Because it was so narrow, even with an army as large as the Persians had, only a small number could actually fight at any one time. This enables very few men to hold off enormous armies for long amounts of time.
The Greek army was about 10,000 strong and already in position when Xerxes and his army arrived. The Greek army was being led by the Spartan king Leonidas. The Persian Army attacked, but the Greeks held fast, and the Persian army suffered heavy losses. Time and time again the Persians attacked, but were turned away…