Sydney Opera House is a masterpiece of architecture. The beautiful, curving sails welcome all those who enter Sydney Harbour. In 1954 the NSW Government called an open-ended international design competition. Architect Jørn Utzon’s entry won the competition. Utzon understood and recognised the potential the site had with Sydney Harbour as a stunning backdrop. His design called for distinct roofs of interlocking shells with each shell derived from the surface of a sphere. The radical design of the vaulted roof shells took years to develop leading to huge cost overruns. The original estimated cost of $7 million reached $102 million by the end of construction. The estimated timeframe of construction stretched from four years to fourteen years, beginning in 1959, and ending in 1973. In 1966 after years of cost overruns, the new NSW government refused to cooperate with Utzon’s plans. Utzon was forced to resign leading to public outcry, street demonstrations, and professional controversy. The Sydney Opera House finally opened in 1973. In 1999 Utzon was asked to design a set of principles to act as a guide for all future changes to the building. Today, the Sydney Opera House is a UNESCO World Heritage site and the symbol of both Sydney and the Australian nation.