1939 old movie clip about the fort : http://aso.gov.au/titles/newsreels/australia-to...
Fort Denison has been at the heart of Sydney Harbour for over 150 years and over that time has had a varied past – it has been used as a fishing spot, defence structure, navigational guide, tide gauge station, weather station, time marker and now a restaurant, events space and historic museum.
Fort Denison was once a small, rocky island referred to by the local Aboriginal people as Mat-te-wan-ye, also spelt Muttewai.
After the First Fleet arrived in 1788, Governor Phillip renamed the land Rock Island, but it was informally known to locals as Pinchgut, as it was believed convicts were sentenced to weeks at a time isolated on the island with little bread and water.
The island was flattened and quarried for sandstone, which wa used in the building of Bennelong Point, where the Opera House now stands. Once flatteneted the fortification was completed in 1857. Built from 8000 tonnes of sandstone, quarried near Kurraba Point, Neutral Bay, the island was named Fort Denison, after Sir William Thomas Denison, who was the Governor of New South Wales at the time.
The fort features the only Martello Tower to be built in Australia, and the final one ever constructed in the British Empire.
From 1906 to 1942, the One O’clock Gun was fired each day to enable sailors to correctly set their ship’s chronometer to the local time. The firing of the cannon was stopped during World War II to avoid terrifying Sydneysiders and was later resumed in 1986. Currently the cannon is not being fired however NPWS hope to resume this soon .
The island has been managed by various organisations over time, including the Naval Brigade in 1869, and the Sydney Harbour Trust in 1900. Fort Denison became part of Sydney Harbour National Park in 1992, managed by the NSW National Parks & Wildlife Service