A convict prison and then Australia's biggest shipyard, on an island in the harbour where you can camp overnight.
Wareamah, the island’s Aboriginal name, is the largest island in Sydney Harbour, and it has been used for two things that between them explain a great deal of Australian history: imprisoning convicts and building ships.
It is one of the eleven Australian Convict Sites on the UNESCO World Heritage list.
The prison
From 1839 it held convicts, initially those who had reoffended in the colony — men transported twice over. They quarried the sandstone, cut silos into the rock by hand, and built the barracks and the perimeter walls that still stand.
After transportation ended it became a reformatory for girls and an industrial school, then a gaol again.
Conditions were harsh even by the standards of the system, and the underground solitary cells cut into the rock are open to walk into.
The shipyard
From 1857 the island became a dockyard, and from the 1890s the principal shipbuilding and repair yard in Australia. It built and serviced warships through both world wars, employed several thousand people at its peak, and closed in 1992.
The industrial fabric is largely intact: turbine shops, cranes, the Fitzroy Dock — dug by convicts and the oldest dry dock in Australia — the Sutherland Dock, machine shops with the machines still in them.
The combination is what makes the island unusual. Convict sandstone and twentieth-century industrial steel occupy the same few hectares, and you walk from one to the other.
Visiting
Free to land and walk. Self-guided routes are signposted and there is an audio tour. Guided tours run at weekends and cover areas otherwise closed.
Camping is the distinctive option: pre-pitched tents or your own on a lawn above the water, with facilities, a café and the entire island to yourself after the last ferry. Book early for summer and school holidays.
There is also glamping and some heritage-house accommodation.
The Biennale
Cockatoo Island is a principal venue of the Biennale of Sydney, and the industrial halls make extraordinary spaces for large-scale installation. If a Biennale is on — every two years, autumn — the island is the reason to go.
Concerts and festivals also use it.
Practicalities
Ferries from Circular Quay, Barangaroo and Darling Harbour on an Opal card, about 25 minutes.
There is a café and a bar. The ground is uneven, hilly and industrial; sturdy shoes.
Check the last ferry time before you settle in, unless you are camping.
More History
Hyde Park Barracks
A convict dormitory of 1819 that became an immigration depot and an asylum, and is now the best museum of any of it.
Barangaroo Reserve
A container terminal turned back into a sandstone headland, named for a Cammeraygal woman who refused to wear English clothes.