Winning the right to host the Olympic Games is widely regarded as the most significant prize on offer in the never-ending contest between the world's leading cities for prestige and investment. This essay explores the implications and significance of being an Olympic city. After recognising the Olympics as a mega-event with inherent mega-project tendencies, it provides a chronological survey that shows the changing agendas that host cities have brought to bear on staging the Games. The increasing scale of their ambitions is noted, particularly with respect to urban regeneration and city rebranding, while also recognising the financial and human costs involved. The next part throws light on contemporary practice through a study of the proposals for the Lower Lea Valley in London's East End – the site of the future Olympic Park for the 2012 Summer Games. The conclusion suggests an evolving research agenda, framed particularly around the London 2012 Games and the notion of legacy.