The Sydney central business district (CBD) is the historical and main commercial centre of Sydney. The CBD is Sydney's city centre, or Sydney City, and the two terms are used interchangeably. Colloquially, the CBD or city centre is often referred to simply as "Town" or "the City". The Sydney city centre extends southwards for about from Sydney Cove, the point of first European settlement in which the Sydney region was initially established. Due to its pivotal role in Australia's early history, it is one of the oldest established areas in the country. Geographically, its north–south axis runs from Circular Quay in the north to Central railway station in the south. Its east–west axis runs from a chain of parkland that includes Hyde Park, The Domain, Royal Botanic Gardens and Farm Cove on Sydney Harbour in the east; to Darling Harbour and the Western Distributor in the west. The Sydney City is Australia's main financial and economic centre, as well as a leading hub of economic activity for the Asia Pacific region. The city centre and areas immediately around it employ approximately 22% of the Sydney region's workforce. The City has the largest gathering of workers in the whole of Sydney. Most of them are white collar office workers in the finance and professional service industries. In 2012, the number of workers operating in the City was 226,972. Based on industry mix and relative occupational wage levels it is estimated that economic activity (GDP) generated in the city in 2015/16 was approximately $118 billion. Culturally, the city centre is Sydney's focal point for nightlife and entertainment. It is also home to some of the city's most significant buildings and structures. Geography and urban structure The Sydney CBD is an area of very densely concentrated skyscrapers and other buildings, interspersed by several parks such as Hyde Park, The Domain, Royal Botanic Gardens and Wynyard Park. George Street is the Sydney CBD's main north–south thoroughfare. The streets run on a slightly warped grid pattern in the southern CBD, but in the older northern CBD the streets form several intersecting grids, reflecting their placement in relation to the prevailing breeze and orientation to Circular Quay in early settlement. The CBD runs along two ridge lines below Macquarie Street and York Streets. Between these ridges is Pitt Street, running close to the course of the original Tank Stream (now tunneled). Bridge Street took its name