Battle of Thermopylae
The Battle of Thermopylae was a famous battle during the Greco-Persian Wars. It is known for the fact that 300 Spartan soldiers and 7000 other Greek soldiers (most notably the Thespians) held off an army of several hundred thousand Persian soldiers (led by Xerxes) for three days.
The most recognized battle of Thermopylae was that of the Greeks and Persians around 480 BC. The Persian "God" king Xerxes was waging war on Greece for control of its lands and people. The battle is most known for the impressive show of strength by the Persians, whose forces numbered between 2 million and 200,000. The battle is also known for the determination and bravery of the roughly 7000 Greeks. The estimated 6700 Athenians (and soldiers from other city-states) were led by the Spartan king Leonidas. The Greek soldiers were able to successfully hold off the Persians because of the terrain and their fighting style. Because the mountain pass was so narrow, the Greeks only had to fight a small number of the persian army at a time. Also, the Greek phalanx, a fighting style consisting of ten rows and ten columns of soldiers carrying twelve foot long spears and rounded shields gave the Greeks a huge advantage. This fighting style was so effective because the tight formation and shields left practically no part of a soldier unprotected, and the twelve foot long spears enabled men from a few rows back to attack. It was also effective because when a Greek soldier died on the front line, he was immediately replaced by a new soldier. After two days of battle, a traitorous Greek farmer named Ephialtes told the Persians of a secret path that let the Persians get around and attack the Spartans from behind. 300 Spartans stayed, while the Athenians left to gather more forces, and the impressive last stand by the Spartans allowed Sparta and Athens to regroup and eventually defeat the Persian forces in a later battle. It is also estimated that 20,000 Persians were killed by the allied force. The traitor Ephialtes is so derided in Greek tradition, that his name is now a synonym for "nightmare."
A movie was made about this battle in 2007 named "300". However, the movie was based upon the highly-stylized graphic novel by Frank Miller and not upon historical fact.
Cartledge, Paul, Thermopylae; the Battle that Changed the World, Overlook Press, New York, 2006