Sydney, Australia is located in a coastal basin bordered by the Pacific Ocean to the east, the Blue Mountains to the west, the Hawkesbury River to the north and the Woronora Plateau to the south. Sydney lies on a submergent coastline, where the ocean level has risen to flood deep river valleys carved in the sandstone. One of these drowned valleys, Port Jackson, better known as Sydney Harbour, is the largest natural harbour in the world. There are more than 70 harbour and ocean beaches, including the famous Bondi Beach, in the urban area. Sydney's urban area covers 1687 km² as at 2001. The Sydney Statistical Division, used for census data, is the unofficial metropolitan area and covers 12,145 km² . This area includes the Central Coast and Blue Mountains as well as broad swathes of national park and other non-urban land. Geographically, Sydney sprawls over two major regions: the Cumberland Plain, a relatively flat region lying to the south and west of the harbour, and the Hornsby P More »