Built between the 11th and 13th centuries, Bonn Minster (German: Bonner Münster) features a masterful blend of Romanesque symmetry and Gothic transition. It is crowned by five towers with a 315-foot (96-meter) central crossing spire. Two large granite head monuments sculpted by Iskender Yediler rest on the outdoor plaza, depicting its two patron saints: Saints Cassius and Florentius.