AS THE SPANISH ARMADA cruised into the English Channel, it looked like a fearsome city under sail. The mission of the most heavily armed fleet the world's greatest naval power had ever put to sea was simple: meet the British navy and crush it. Then King Philip II's ally, the Duke of Parma, would sail north from Dunkirk and invade England. His troops, Philip assumed, would be embraced by English Catholics, who would rise in rebellion and hurl the Protestant Queen Elizabeth I from her throne.

But on July 29, 1588, an English fleet of substantially smaller ships began destroying the armada. Many of these ships were of a radical new design: low, streamlined, nimble. To exploit their advantage, the English unveiled a completely new method of naval combat, making no attempt to board the enemy ships, relying instead on their long-range cannon. Only half of the Spanish ships made it home.

The armada's defeat was a portent of much to come. True, the Spanish empire declined gradually, and it would be a century before Britannia ruled the waves. But the British Lion had roared.