20 Oct 1973 - Sydney Opera House officially opened
On this day 20 October 1973 the Sydney Opera House was officially opened by Queen Elizabeth II.
Work had began on the building in 1959 and was completed in 1973 at a cost of $102 million. The official opening was celebrated with fireworks and a performance of Beethoven's Symphony No. 9.
The first public performance was the month before on 28 September 1973.
The Sydney Opera House stands on Tubowgule land of the Gadigal people.
Source: Sydney Opera House. (2021). A grand opening
Sydney Opera House booklets

Sydney Opera House - the Gold Book
The printed booklet, commonly known as the “Gold Book”, was issued to accompany the “Ceremony to Commemorate the Commencement of the Sydney Opera House” on 2 March 1959

Sydney Opera House - the Red Book
This 1958 report (known also as the Red Book) was presented by Jørn Utzon to the Premier and the Sydney Opera House Committee in order to give … a project which realizes in practical form the vision of the competition

Sydney Opera House - the Brown Book
Conditions and Programme for an International Competition for a National Opera House at Bennelong Point, Sydney, New South Wales, Australia
Related

Sydney Opera House guide
A brief history of the Sydney Opera House plus a select list of records relating to the design, construction and official opening

The 1954 Royal Tour
On 3 February 1954, Queen Elizabeth II and Prince Philip, Duke of Edinburgh arrived at Farm Cove in Sydney to commence their Royal Tour of Australia