Why did Revere need a signal from the Old North Church?
"This signal, from the tallest structure in the town of Boston, served as an early warning that a detachment of the British Army was crossing the Charles River and heading west towards the towns of Lexington and Concord. By the end of the next night, the American Revolutionary War had begun."
The place for the signal, the Old North Church in Boston's North end was chosen for two reason.
The signal was meant to warn patriots in Chalrestown, and across the river from Boston in case Paul Revere couldn't deliver the message there from Boston to start his ride.
