Millennium celebrations

On Earth, the millennium celebrations were a worldwide, coordinated series of New Year events celebrating the end of 1999 and the start of the year 2000 in the Gregorian calendar, marking the end of the 20th century and the beginning of the 21st century. (PROSE: The Novel of the Film)

Controversy
There were differing opinions as to whether the year 2000 or 2001 was the start of the third millennium. American news outlets and world-renowned chronologist Professor Wagg considered 2000 the start of the third millennium. (TV: Doctor Who) This view was shared by at least the Eighth Doctor. (PROSE: The Novel of the Film) Despite the predilection of most humans to celebrate it as the beginning of the millennium, however, at least the Sixth Doctor regarded it as the final year of the second millennium. (PROSE: Millennial Rites) This tug-of-war between pedantic and common conception of the year was reflected in an argument had between Anji Kapoor and her boyfriend Dave Young. He held fast to the technically correct view that 1 January 2001 was the beginning of the millennium, whereas she found this an example of why she was seriously considering leaving him. (PROSE: Escape Velocity)

Events
In 1998, the Grand Metropolitan Opera House was built in San Francisco to commemorate the forthcoming millennium. (PROSE: The Novel of the Film)

In the days leading up to the New Year, the staff of Walker General Hospital in San Francisco worked overtime, anticipating a greater number of accident and emergency cases than most New Year's Eves in the past. (PROSE: The Novel of the Film)

Operating according to time zones, parts of the world such as Moscow welcomed in the New Year one by one. Footage of these events was broadcast by British television media before attention was turned to the coming of 2000 in the UK, with mass celebrations occuring in the cities of Cardiff and London, where a fireworks display was held outside Big Ben, (TV: Fragments) from Times Square, Trafalgar Square, La Place du Concord, to Red Square. (PROSE: The Novel of the Film)

The Thirteenth Doctor and Team TARDIS enjoyed the New Year's celebrations at Sydney Harbour Bridge, which Graham O'Brien nearly fell off. This was Ryan Sinclair's favourite New Year. (TV: Resolution)

The Fourth Doctor stopped the Y2K bug as the New Year arrived. (PROSE: Millennium Shock)

The Seventh Doctor and Melanie Bush gate crashed the New Year's Eve party being thrown by Alisha Hammerson, the Auton head of Hammerson Plastic PLC, in London. They foiled her plan to replace her guests with Auton replicas so the Earth could be dominated and absorbed by severing her link to the Nestene Consciousness. (COMIC: Plastic Millennium)

Having been driven insane by the Last of Erebus, which showed him dark things awaiting in the future, Torchwood Cardiff leader Alex Hopkins planned to kill his teammates out of "mercy". While Jack Harkness, Torchwood's immortal operative, was dealing with a "Millennium Bug" of his own, Alex shot the remaining members. As he did so, Alex spoke to Yvonne Hartman at Torchwood One of his epiphany. (AUDIO: One Rule) With just minutes to go until midnight, Jack returned to the Hub where he found what Alex had done. Observing the broadcast of the countdown from London, Alex told Jack of what he had seen and gave command of Torchwood Cardiff over to him before killing himself the moment the New Year arrived. (TV: Fragments)

In America, parties were held for the New Year at Walker General Hospital and the Institute for Technological Advancement and Research in San Francisco, where coverage of the worldwide celebrations was broadcast by KKBE. Shortly after midnight, the newly regenerated Eighth Doctor, having just saved the Earth from, returned Grace Holloway and Chang Lee to San Francisco, where a fireworks display was being held. After receiving a kiss from Grace, the Doctor left in the TARDIS. (TV: Doctor Who)

Behind the scenes

 * In the years leading up to the real world millennium celebrations, the 1990s saw several Doctor Who stories depicting the forthcoming events: Plastic Millenium, published December 1994, Millennial Rites, published 19 October 1995, Doctor Who and its novelisation The Novel of the Film, broadcast on 14 May and published 16 May 1996, and Millennium Shock, published 10 May 1999.
 * Dapol, which produced a range of toys based on the classic series of Doctor Who, released a set of six "Millennium Daleks" to commemorate the millennium. Sparkly with a golden neck grille, slats and sense globes, the six Daleks' main casings were respectively coloured blue (W008-M1), red (W008-M2), green (W008-M3), purple (W008-M4), black (W008-M5) and silver (W008-M6).