Arrecife (Lanzarote) - Blink and miss it. Where all the locals live, fuck knows why.
Essen (thanks to Al Bol for the reminder) - Stopped off there once off for a comfort break, never again. 60's concrete hell and Germany's answer to Coventry minus the curry houses. Remember it's fun fun fun on the Autobahn so stay on it til you've gone well past.
Kaliningrad - Once a historic baltic port city reduced to a crime-ridden, disease infested shithole. Dangerous place, stay away.