Parliament House is the meeting facility of the Parliament of Australia located in Canberra, the capital of Australia. The building was designed by Mitchell/Giurgola Architects and opened on 1988 by Elizabeth II, Queen of Australia. Costing more than A$1.1 billion, it was the most expensive building in the world at the time of its construction.Federal Parliament meetings were first held in Melbourne until 1927. Between 1927 and 1988, the Parliament of Australia met in the Provisional Parliament House, which is now known as "Old Parliament House". Construction of Australia's permanent Parliament House was delayed while its location was debated. Construction of the new building began in 1981. The principal design of the structure is based on the shape of two boomerangs and is topped by an 81-metre flagpole. It contains 4,700 rooms and many areas are open to the public. The main foyer contains a marble staircase and leads to the Great Hall which has a large tapestry on display. The House of Representatives chamber is decorated green while the Senate chamber has a red colour scheme. Between the two chambers is the Members' Hall which has a water feature and is not open to the public. The Ministerial Wing houses the office of the Prime Minister and other Ministers.Before the establishment of CanberraIn 1901, when the six British colonies in Australia federated to form the Commonwealth of Australia, Melbourne and Sydney were the two largest cities in the country, but the long history of rivalry between them meant that neither could become the national capital. Section 125 of the Constitution of Australia therefore provided that: