On 20 October 1973, the Sydney Opera House was officially opened by Queen Elizabeth II. From conception to completion, it had taken more than 15 years and over $100 million dollars. In the years since its completion, the Sydney Opera House has become one of the most identifiable of Australia’s icons - ranking with the Sydney Harbour Bridge, Uluru, the koala and kangaroo - and is considered by many to be among the world's great architectural masterpieces.