Today a National Historic Site, this Martello tower was built in 1813 to defend the city and was also used in both World Wars. During World War II, a structure was added to house the antiaircraft headquarters of Saint John. Inside the tower are displays relating to local military history. Rising above its surroundings, the tower commands a sweeping view which embraces the town, the harbour, the docks, the railway yards and a breakwater that leads to Partridge Island.