Hmmm, guys. Thanks. You almost convinced me to go to Dusseldorf on Monday aftrnoon, but it will be really hard to have some fun in german industrial town, if I come back from lively Madrid

. Well, I will try anyway...
Duesseldorf an industrial town??? Duisburg is for sure and perhaps even Cologne but in Duesseldorf you would have to go far into the suburbs (e.g. Holthausen for Henkel) to meet any substantial industry activity - agree with previous posters - Duesseldorf is just fine, don't bother with Cologne for 5h layover