My grandmother lived in Dusseldorf until she was 8. I got to see the house she lived in (http://picasaweb.google.com/42itous/MiniGrandTour?authkey=bMX3SZmY5eA#5206187378699124610), and the site where her grandparents lived (though their house was torn down in about the 60s). We had a very nice day wandering around Dusseldorf -- we took a boat tour (their Gehry building is as ugly as ours) and we went to the Aquazoo.