a significant number from outside Australia. Another prominent park in the west is the Western Sydney Regional Park in Abbotsbury. The greater west also includes Sydney Olympic Park, a suburb created to host the 2000 Summer Olympics, and Sydney Motorsport Park, a motorsport circuit located in Eastern Creek. The Boothtown Aqueduct in Greystanes is a 19th-century water bridge that is listed on the New South Wales State Heritage Register as a site of State significance. Prospect Hill, a historically significant ridge in the west and the only area in Sydney with ancient volcanic activity, is also listed on the NSW State Heritage Register. To the northwest, Featherdale Wildlife Park, an Australian zoo in Doonside, near Blacktown, is a major tourist attraction, not just for Western Sydney, but for NSW and Australia. Sydney Zoo, opened in 2019, is another prominent zoo situated in Bungaribee. Westfield Parramatta in Parramatta is Australia's busiest Westfield shopping centre, having 28.7 million customer visits per annum. Established in 1799, the Old Government House, a historic house museum and tourist spot in Parramatta, was included in the Australian National Heritage List on 1 August 2007 and World Heritage List in 2010 (as part of the 11 penal sites constituting the Australian Convict Sites), making it the only site in greater western Sydney to be featured in such lists. Moreover, the house is Australia's oldest surviving public building. Further to the southwest is the region of Macarthur and the city of Campbelltown, a significant population centre until the 1990s considered a region separate to Sydney proper. Macarthur Square, a shopping complex in Campbelltown, has become one of the largest shopping complexes in Sydney. The southwest also features Bankstown Reservoir, the oldest elevated reservoir constructed in reinforced concrete that is still in use and is listed on the New South Wales State Heritage Register. The southwest is home to one of Sydney's oldest trees, the Bland Oak, which was planted in the 1840s by William Bland in the suburb of Carramar. Urban structure Architecture The earliest structures in the colony were built to the bare minimum of standards. Upon his appointment, Governor Lachlan Macquarie set ambitious targets for the architectural design of new construction projects. The city now has a world heritage listed building, several national heritage listed buildings, and dozens of Commonwealth heritage listed buildings as evidence of the survival of Macquarie's ideals. In 1814 the Governor called