opera house located on Port Jackson (Sydney Harbour), New South Wales, Australia. Its unique sail-like design makes it one of the most photographed buildings in the world.

In 1957 Danish architect Jørn Utzon (Utzon, Jørn) won the design competition for a new opera house at Bennelong Point in Sydney with a dramatic design that brought him international fame. Construction, however, posed a variety of problems, many resulting from the innovative nature of the design, a series of sail-like shells. He resigned from the project in 1966, but construction continued until September 1973. The completed Opera House is now Sydney's best-known landmark. In 1999 Utzon agreed to return as the building's architect, overseeing an improvement project. He redesigned the reception hall—the only interior space that had been true to his plans—and it opened in 2004 as the Utzon Room. Two years later a new colonnade was completed, marking the first alteration to the Opera House's exterior since 1973. In 2007 the Opera House was designated a UNESCO World Heritage site.