Sydney is Australia 's oldest city, the economic powerhouse of the nation and the country's capital .The Sydney Opera House is situated on Bennelong Point in Sydney Harbour, close to the Sydney Harbour Bridge. It sits at the northeastern tip of the Sydney central business district surrounded on three sides by the harbour and neighboured by the Royal Botanic Gardens.The building covers 1.8 hectares (4.5 acres) of land and is 183 metres (605 ft) long and 120 metres (388 ft) wide at its widest point.