MAINZ, GERMANY—Traces of a 1,200-year-old church have been discovered incorporated into the 1,000-year-old “Old Cathedral” in Mainz. The older walls, which date to the time of Charlemagne, stretch from the basement to the roof. “This is the only surviving Carolingian cathedral in Germany,” Rhineland-Palatinate state curator Joachim Glatz told The Local. Two burials dating to the time of the earlier church have also been found. The building was severely damaged during World War II.