Cities of the Ruhrgebiet

[Jona Lendering]

OK, let's face it: the Ruhrgebiet is not the first part of Europe that comes to mind when you think about "nice old towns and beautiful scenery". Still, I am urgently looking for a hotel for about twenty people in a city that offers several restaurants and a possibility to walk around a bit. (It's for a group that has already visited Kalkriese and Haltern and will next day proceed to Bonn and Cologne.)

Are there cities that can be recommended? Please tell me if it is possible to stay in Bochum, Herne, Dortmund, Essen or Gelsenkirchen, or perhaps Oberhausen... (Hotel recommendations appreciated as well.)