Xanten Cathedral

Xanten Cathedral, sometimes called St. Victor's Cathedral, is a Roman Catholic church situated in Xanten, a historic town in the lower Rhine area, North Rhine-Westphalia, Germany. It is considered the biggest cathedral between Cologne and the sea. In 1936 it was declared a minor basilica by Pope Pius XI.

Even though the church is called a cathedral, it has never been the seat of a bishop.

Source: Wikipedia