Kaiserwerth
Kaiserswerth is a beautiful historic site, and wasn't actually part of Düsseldorf until 1929. It is reachable by tram or car, and functions as a recreation area for the city folk. Go for a walk by the ruins of the castle along the Rhine, have a break at one of the beer gardens or market cafes, or treat yourself to a three—star meal by Jean-Claude Bourgueil.