the `holzturm` in mainz

15th ancient appearance architecture bank beautiful blue building century city construction current dates day defence early europe european exterior facade gaol gate german germany gothic high history holz holzturm iron landmark mainz mediaeval medieval named old one outside palatinate piled prison reconstructed red remaining retro rheinhessen rhine rhineland roof sandstone six sky stone storey summer three touristic tower towers town turm used view wall walls watchtower white window wood