Leading Sydney citizens used to complain that Sydney, unlike many smaller cities in Europe and America, lacked a large modem center for the arts. Public pressure became so great that a committee was finally set up to look into the situation and make proposals. It considered thirty possible sites before it chose Bennelong Point. The Government decided to find a design for an Opera House by holding a worldwide competition. The prizes were quite small, but the winner could expect to earn a lot more when he designed the working plans and took charge of the construction. An international group of judges received designs from more than thirty-two countries. They all agreed that the first prize should go to Iota Utzon, who had sent in a highly imaginative, bold design of a great building that looked like a beautiful concrete butterfly. They nevertheless commented that Utzon's drawings lacked detail. They were thought to go beyond the limit of existing technology. Even before the difficult construction work began on the roof, the engineering firm had to face unusual technical problems in building the platform. About seven hundred concrete piers (码头) had to be sunk to a depth of thirteen meters in Sydney Harbor to support the building. The company ran into so many difficulties that they had to be paid twice as much as was originally agreed upon. Almost six years were needed to work out a way of building the platform. Thousands of calculations were made using a computer. Utzon had had disagreements with many engineers. But most Australians are extremely proud of this house which stands on the finest site of any public building constructed this century. From the passage we can see that this building ______.