<Tr> <Th> Awards and prizes </Th> <Td> Royal Academy of Engineering MacRobert Award </Td> </Tr> <P> The Millennium Dome, also referred to simply as The Dome, is the original name of a large dome - shaped building, originally used to house the Millennium Experience, a major exhibition celebrating the beginning of the third millennium . Located on the Greenwich Peninsula in South East London, England, the exhibition was open to the public from 1 January to 31 December 2000 . The project and exhibition was the subject of considerable political controversy as it failed to attract the number of visitors anticipated, with recurring financial problems . All of the original exhibition and associated complex has since been demolished . The dome still exists, however, and it is now a key exterior feature of The O2 . The Prime Meridian passes the western edge of the Dome and the nearest London Underground station is North Greenwich on the Jubilee line . </P> <P> The dome is one of the largest of its type in the world . Externally, it appears as a large white marquee with twelve 100 m - high yellow support towers, one for each month of the year, or each hour of the clock face, representing the role played by Greenwich Mean Time . In plan view it is circular, 365 m (one metre for each day in a standard year) in diameter . It has become one of the United Kingdom's most recognisable landmarks . It can easily be seen on aerial photographs of London . Its exterior is reminiscent of the Dome of Discovery built for the Festival of Britain in 1951 . </P> <P> The architect was Richard Rogers and the contractor was a joint venture company, McAlpine / Laing Joint Venture (MLJV) formed between Sir Robert McAlpine and Laing Management . The building structure was engineered by Buro Happold, and the entire roof structure weighs less than the air contained within the building . Although referred to as a dome it is not strictly one as it is not self - supporting, but is in fact a giant Big Top, the canopy being supported by a dome - shaped cable network, from twelve king posts . For this reason, it has been disparagingly referred to as the Millennium Tent . The twelve posts represent the twelve months of the year, another reference to time in its dimensions, alongside its height and diameter . </P>

What is the diameter of the millennium dome