SPEYER CATHEDRAL, Germany: is the seat of the Roman Catholic Bishop of Speyer. It was completed in 1106, &amp; was extremely influential in the subsequent development of Romanesque architecture during the 11th and 12th centuries. Conrad II commissioned the cathedral to be the Catholic world&#39;s largest church as well as his own tomb. It was one of the most ambitious projects of its time &amp; when completed was one of the largest buildings in the world.