After days of watching the British prepare, bursts of smoke signaled their attack from Anastasia Island. A sentry in the San Carlos watchtower yelled and rang the bell, quickly alerting the garrison that the British were firing at the Castillo. Soldiers surged to their posts or ran for cover. This began a 38-day siege in 1740. In the end, cannon fire partially damaged the eastern outer wall, and the bombardment killed two townspeople.