To mark the birth of a new millennium the controversial dome was built as the focal point of London's New Year 2000 celebrations. Just a short distance from the Greenwich Royal Observatory it is on the line where Greenwich Mean Time ushers in the new year. This is the largest single structure in the UK and cost over £50 million. It was open for just one year as a showcase of the achievements of the last 1,000 years and is now closed to visitors.