Sydney Opera House

A performing-arts centre famed for its sail-like shell roofs, one of the great buildings of the 20th century.

Inside are several theatres and concert halls that together host more than 1,800 performances a year, from opera and orchestra concerts to plays. It is one of Australia's most visited places and is seen as a masterpiece of 20th-century architecture. UNESCO named it a World Heritage Site in 2007, describing it as a daring and visionary experiment that changed modern architecture.

History

Long before the building, Bennelong Point, known to Aboriginal people as Tubowgule, was a place for ceremony and gathering. In 1957 Jørn Utzon won an international design competition, and construction began on 2 March 1959. The project grew far more difficult and expensive than planned. After arguments with the government over cost and design, Utzon resigned in 1966 and left Australia. A team led by Australian architect Peter Hall finished the building, especially the interiors. The final cost was about A$102 million.

How the shells were built

For years nobody could work out how to build Utzon's curved roofs. The breakthrough came when Utzon realised that every shell could be cut from the surface of the same imaginary sphere, about 75 metres in radius. That meant the pieces could be made in a factory from repeated shapes, using precast concrete ribs. The engineering firm of Ove Arup helped turn the idea into reality. The shells are covered in more than a million tiles in two colours, glossy white and matte cream, laid in a gentle chevron, or V-shaped, pattern.

On the globe

The model shows the Opera House's sail-like shell roofs on their point of land beside Sydney Harbour. Look for how the shells overlap and rise toward the water.