Gelsenkirchen
(credit: Gelsenkirchen, Stadtmarketing Gesellschaft)
Gelsenkirchen is an industrial city in the northern part of the Ruhr valley. While it was famous in the early 20th century for its prolific coal mining, it is now one of the most forthright active campaigners for solar technology, and is home to the world's largest solar power plant.
One of the most noticeable things about Gelsenkirchen is just how green it is. It is hard to walk anywhere that is not surrounded by tree-lined avenues and parks.
Added to this, it is a thoroughly modern city, with the technologically impressive new stadium for local football team, Schalke 04. This rubs shoulders with a sense of medieval history, with popular follies including Berge Castle.