Sometimes it takes just one human being to tip the scales and change the course of history. At some point in the year 2007, that human being will either move to a city or be born in one. The event itself will go unnoticed but demographers watching urban trends will mark it as the moment when the world entered a new urban millennium, a period in which, for the first time in history, the majority of the world’s people will live in cities. The year 2007 will also see the number of slum dwellers in the world cross the one billion mark – when one in every three city residents will live in inadequate housing with no or few basic services. This statistic may be reported in newspaper headlines, but it is still not yet clear how it will influence government policies and actions, particularly in relation to Millennium Development Goal 7, target 11: by 2020, to have improved the lives of at least 100 million slum dwellers.