Norfolk Naval Shipyard Nine O'Clock Gun
Around 1850 the Norfolk Naval Shipyard (Then known as The Gosport Shipyard) began firing a gun every night at exactly 9pm. The shot could be heard throughout Portsmouth and much of Norfolk.
Originally suggested by a local newspaper editor in 1847, the purpose was for ships and residents to synchronize their chronometers and clocks to the correct time. It also took on another unintended purpose in that many families used it as a curfew for their children
For over 150 years the shot was a tradition with very few interuptions. It was stopped for approximately 2 years beginning in 1907 when an officer's wife complained it was disturbing the sleep of her newborn child, and again after the terrorist attacks of 9/11 to prevent startling citizens.
The tradition was restarted for a while but there were difficulties with staffing and training.This combined with the advance of technology made it obsolete for military purposes. The tradition has now been permanently discontinued.