The Sydney Opera House is an expressionist modern design, with a series of large precast concrete ‘shells’, each taken from a hemisphere of the same radius, forming the roofs of the structure. The Opera House covers 1.8 hectares (4.5 acres) of land. It is 183 metres (605 feet) long and about 120 metres (388 feet) wide at its widest point. It is supported on 580 concrete piers sunk up to 25 metres below sea level. Its power supply is equivalent for a town of 25,000 people. The roofs of the House are covered with 1.056 million glossy white and matte cream Swedish-made tiles.