Sydney Opera House, opera house located on Port Jackson (Sydney Harbour), New South Wales, Australia. Its unique use of a series of gleaming white sail-shaped shells as its roof structure makes it one of the most-photographed buildings in the world.

The Sydney Opera House constitutes a masterpiece of 20th century architecture. Its significance is based on its unparalleled design and construction; its exceptional engineering achievements and technological innovation and its position as a world-famous icon of architecture. It is a daring and visionary experiment that has had an enduring influence on the emergent architecture of the late 20th century.