How many islands in Sydney Harbour can you name? There were once 14 islands in Sydney Harbour - Shark, Clark, Fort Denison, Goat, Cockatoo, Snapper and Rodd islands, Spectacle (two into one), Garden, Bennelong, Darling, Glebe and Berry islands. If you just counted, you'll notice we've only named 13 and that's because Spectacle island has been reclaimed and formed from two outcrops. The islands in Sydney Harbour were once the outcrops and the peaks of steep hills and they were basically left uncovered as the sea level rose, between 10,000 and 6,000 years ago, flooding an ancient river valley and forming the harbour that exists today. We also have an inkling about some of the Aboringinal names for the islands. The early colonial record suggests that the islands were called Boambilly (Shark Island), Billong-olola/Be-lang-le-wool (Clark Island), Ba-ing-hoe/Booroowang (Garden Island), Mat-te-wan-ye (Pinchgut/Fort Denison), Me-mel/Milmil (Goat Island), Wa-rea-mah (Cockatoo Island), Ar-ra-re-agon (Snapper Island) and Gong-ul (Spectacle Island). The islands have a rich history that reflects the Aboriginal, colonial, industrial, scientific, naval and social developments of Sydney. And there are many fascinating facts to discover about what's gone on at these places. For example, Shark Island sits in Sydney Harbour, just 1km from Rose Bay. In 1945, the first Sydney to Hobart race was launched from its banks. Rodd Island became the centre of scientific experiments in the 1880s to try and control the rabbit population. There's been convict hard labour, the water police, shipyards, and picnics on the various islands. Cockatoo Island is pretty fascinating, and that's one island you can visit, especially with the Biennale of Sydney happening at the moment. Over the next few weeks we will be looking at some of the different islands and their histories. In the meantime, check out our essay about the islands written by the talent historian Ian Hoskins for the Dictionary and supported by the Australian National Maritime Museum. And if you missed my segment with Sophie yesterday, you can catch up here.