Although it's still known as an "island," this promontory was connected with the mainland in 1942. During the 1941–45 War of the Pacific (WWII and a number of preceding conflicts), Australia's largest naval base and dockyard was a frontline port for Allied ships. Part of the naval base is now open to the public. Access, seven days a week, to the site is via ferry from Circular Quay (take the Watsons Bay ferry). Visitors can view the museum (A$5) and picnic on the hill.
The Naval Historical Society runs tours to the "secure" section of Garden Island and these must be booked well in advance. The 90-minute tours (A$15) run every Thursday and include morning tea and a video. Bookings are made by calling the society or through the website.
Sydney, New South Wales, Australia