Sitting in the middle of Sydney Harbour, Cockatoo Island is a World Heritage listed location with a wealth of history to uncover. In search of some truths about the island's dark past as the Australian answer to Alcatraz, Sara Chare follows the Cockatoo Island Convict Trail.

Australia itself was once considered to be one big prison, what with the transportation of thousands of British convicts to the country between 1788 and 1868, and on 23 February 1839, sixty prisoners arrived on Cockatoo Island after Governor George Gipps decided it would be a good place for a new jail. Today, the island welcomes tourists, family day-trippers, and stylish Sydney locals who have come to sip wine and nibble pizza at the Island Bar.

After a 15-minute ferry ride from Darling Harbour, I arrived on the island, which has been a prison twice, the site of a girl’s school, home to Australia’s largest shipyard, and is now a World Heritage listed site because of its intrinsic historic value. There are a number of self-guided walks charting its history but I had already settled on following the Convict Trail, so after picking up my map I set off.

The first building I came to was the Engineers’ and Blacksmiths’ Shop, a large industrial space held up by steel girders and bricks, and which smelled of pigeons and dust. Built in the 1850s, and despite housing only machinery and empty space, it is a strangely fascinating place that makes you want to whip out your camera and take arty, industrial-chic photographs.

I exited through a tiny blue door reminiscent of Alice in Wonderland, keeping my eye open for the red signs pointing the way, and soon spotted Fitzroy Dock, built over a decade by shackled convicts toiling waist-deep in water. The surrounding buildings were made of sandstone quarried by the first arrivals, and it was here that 550 men were housed in a space meant for 300. Conditions were atrocious: no washing facilities, little or no ventilation. It's little surprise that riots broke out, during which wardens would take potshots at the inmates from the safety of the guardhouse (now a roofless shell). Any ringleaders would be confined for up to a month in one of the twelve underground isolation cells – known as "graves for the living" – with only the rats for company. I shuddered at the thought and moved on, only to discover what remains of some of the six-metre-deep grain silos hewn out of the rock using just hand tools; it's said that if a prisoner did not reach his daily quota of stone, he was not lifted out that day.

Biloela House is the last stop on the trail before taking the stairs back down to ground level. Perched on the highest point of the island it was intended for the superintendent and his family, and sitting on its wide, shady veranda, watching the sailing boats and listening to the sound of seagulls squawking and the ferry horns, I pondered Cockatoo Island’s convict history. With conditions on the island so deplorable and with Sydney so tantalizingly close and visible, most would think about escape, but few tried it. Many of the prisoners couldn’t swim and those that could knew the waters were teeming with sharks as well as rowboat patrols.

The most famous escapee, however, was Frederick Ward, better known as the bushranger Captain Thunderbolt, who was at Cockatoo for seven years for stealing horses. In 1863 he swam successfully to shore after his devoted part-Aboriginal wife Mary Bugg had swum to the island to leave him the tools needed. Mary waited for him on the opposite shore, equipped with her trusty white steed, and the pair eventually rode away to freedom. The law didn’t catch up with Captain Thunderbolt until 1870 when he was shot near Uralla in New South Wales. Luckily for me, I don’t have to wait for a moonless, foggy night to leave the island, there’s a ferry in 30 minutes. That’s just enough time to buy a coffee from the Airstream cafe, admire the harbour and enjoy the fact that times have changed.

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