Garden Island is a thin limestone sliver, 5km off the coast of Western Australia. It was an idyllic holiday destination until it became an important part of the defence of Fremantle during World War 2, protecting the Cockburn Sound and Southern approaches to the port. It was also the training ground of the famous 'Z' Special Unit, who paddled their kayaks into Singapore harbour to attack Japanese shipping. Today it is home to HMAS Stirling and the Royal Australian Navy's Fleet Base West.