Battle of Thermopylae (480 BC)

Three hundred Spartan warriors under King Leonidas held the narrow pass of Thermopylae against an estimated 300,000 Persian invaders for three days. They died to the last man — but bought Greece the time to regroup. The naval victory at Salamis that followed shattered Persian ambitions in Europe for good. Thermopylae's legacy is paradoxically greater in defeat than most victories: it became the ultimate symbol of courage, sacrifice, and the refusal to surrender regardless of odds. Two and a half millennia later, "Come and take them" remains one of the most quoted phrases in military history.