Studded with photogenic industrial relics, convict architecture and art installations, fascinating Cockatoo Island (Wareamah) opened to the public in 2007 and has regular ferry services, a campground, rental accommodation, and two cafe-bars. Information boards and audioguides ($5) explain the island's time as a brutal convict prison, a shipyard and a naval base. A range of tours run from the Visitor Centre, from straight-up heritage tours to Ghostyard Paranormal and Convict Escape Attempts (from $16). The island's a major venue for the Biennale.
A spooky tunnel passes clear through the middle of the island and you can also explore the remains of the prison. During WWII most of the old sandstone buildings were stripped of their roofs and converted into bomb shelters. Solitary confinement cells were unearthed here after being filled in and forgotten in the 1890s.