Refusing to lay down their arms, as British Major John Pitcairn had ordered, the Lexington militia formed ranks to block the soldiers. As the Brits rushed Lexington Green, someone fired a shot. To this day it's not clear which side fired first. Ten Minutemen were killed (some by British bayonets) while ten others were injured. (Follow this link to see the place where the Minutemen formed their line.) One Brit fell, wounded but not dead.
Firing a victory volley, the British soldiers ("Redcoats") marched on toward the North Bridge in Concord. They would not be so fortunate there.
Using their system of spies, 300-400 Minutemen were ready for the Redcoats when they reached Concord. (Follow this linked U.S. Military Academy map to examine the details of the Lexington and Concord fighting.)
As Ralph Waldo Emerson later described it:
By the rude bridge that arched the flood,
Their flag to April's breeze unfurled,
Here once the embattled farmers stood
And fired the shot heard round the world.
By the end of the day, British losses (273) were three times greater than American losses (95). In their retreat from Concord to Boston, the Redcoats sustained more casualties. Legend has it that one British soldier described the retreat (this is a PDF link) as follows:
I never broke my fast for 48 hours, for we carried no provisions. I had my hat shot off my head three times. Two balls went through my coat and carried away my bayonet from my side.
Reconciliation between George III and the colonies was out of the question. Within days, the King declared:
The colonies are in open and avowed rebellion. The die is now cast. The colonies must either submit or triumph.
It would take 6½ years before George III and the colonies knew which side would ultimately triumph. In the meantime, a Charlestown hill was about to lend its name to one of the most famous battles of the American Revolution: Bunker Hill.