The Sydney Opera House has turned 40, and the building's birthday is being celebrated with a week of special events.
Australia's most famous building - at Bennelong Point overlooking Sydney harbour - was the work of the renowned Danish architect Jorn Utzon.
His vision won an international competition run by the New South Wales state government in the late 1950s. But arguments over costs and interior design led to Utzon's resignation.
The project was over budget, finished late and beset by disputes between officials and the architect, yet still the results were spectacular, particularly the majestic roof that resembles a ship at full sail.
Phil Mercer went to take a closer look.