Water-in the form of the Alster Lakes and the Elbe River-is Hamburg's defining feature and the key to the city's success. A harbor city with an international past, Hamburg is the most tolerant and open-minded of German cities. The media have made Hamburg their capital. Add to that the slick world of advertising and you have a populace of worldly and fashionable professionals. Not surprisingly, the city of movers and shakers is also the city with most of Germany's millionaires.