For the first time in history, in the year 2007 more people will live in cities than in rural areas (the so called third urban revolution). Former UN Secretary General Kofi Annan has spoken of the “Urban Millennium.” The rate of urbanization in Asia and Africa is the highest in the world; in the next two decades these shall be the earth’s areas of growth. And by 2030, more than 2 billion people shall relocate to the metropolises and mega cities, especially in Asia. Mega cities, especially in East and Southeast Asia with more than 5 million inhabitants (above all Tôkyô), count as the decisive forces of global change. In almost 60 mega cities around the world more than 600 million people will live there by the year 2015, two-thirds shall be in developing countries, more than half of them in Asia. In Germany the Federal Ministry for Education and Research, the German Research Association and the Helmholtz Association have initiated large research projects on the topic whereby the first two have decisively regional focal points in Asia. In addition, in the year 2008 the International Year of Planet Earth (IYPE) will have their own focal point in the mega cities topic. This symposium shall deal with the topics of “mega urbanization, environment, health, migration, informal sectors, infrastructure” and research in Germany and Japan.