Perth is one of the most isolated state capitals in the world. Located in the south west area region of the vast state of Western Australia, with 1.5 million residents, it contains around 70% of that state's population. Perth is based around the Swan River on a flat coastal plain down from the Darling ranges. The many uncrowded beaches along the Perth coastline also help define the lifestyle; Perth is laid-back, quiet and safe. The centre of the Perth metropolitan area is the Perth CBD located on the Swan River around 10 km inland. The CBD is the premier business and shopping centre, and together with the adjacent Northbridge, the entertainment centre as well. The CBD is about 1 km North-South but 2 km East-West and is centred on the pedestrianised Forrest Place. In or adjacent to Forrest Place you will find the General Post Office (GPO - open Monday - Friday 9-5 and Saturday 9-12), the Tourist Information Centre, Perth Train Station and the Forrest Chase shopping centre including Myer Department store. The main East-West streets are Wellington Street (northern boundary), Murray and Hay Streets (which become pedestrianised shopping malls in the centre), St Georges Terrace/Adelaide Terrace and Riverside Drive (which runs along the Swan River and forms the southern boundary of the CBD). The main northbound street is Barrack Street which runs along the eastern end of the central shopping district and the main southbound street is William Street to the west.