My city Jena
The forstturm (means forest tower) is located in the middle of Thuringian forest and it is a memorial of Franco-German wars from 19th century.
Its hexagonal structure is a beautiful place for photoshooting. The door of the tower is mostly close, but if you are lucky enough, you might get a chance to climb up to the roof of the tower and see the beautiful view over Jena. We had this experience once and it costs 1 Euro per person
More information [here].