Trier Cathedral
Trier Cathedral is Germany's oldest cathedral, built between 310 and 320 in the time of Constantine the Great (306-337). The first cathedral in the 4th century was destroyed by the Franks, and a further destruction took place in 882 during Viking raids in the Rhineland. The most important building phases that followed were in the 10th century (under Bishop Egbert), in the 13th century (for the interior of the cathedral), from the 14th to the 16th century (for the exterior). Restorations were undertaken in the 19th century, to restore it to its medieval appearance, and after the Second World War. Since 1986, Trier Cathedral has been listed as a UNESCO World Heritage Site.