300

[CVD]

It is probably the best known battle to occur in the B.C. era. It's why most people know anything at all about Sparta. If the Spartans hadn't fought at Thermopylae they wouldn't really be remembered quite so well. In one sentence or less it's about 300 Spartans in a narrow pass beating the sh#t out of a million man Persian army for several days/a week in order to buy time for the Greek army to assemble.