Later Gothic towers in Central Europe often followed the French model, but added even denser decorative tracery. Cologne Cathedral had been started in the 13th century, following the plan of Amiens Cathedral, but only the apse and the base of one tower were finished in the Gothic period. The original plans were conserved and rediscovered in 1817, and the building was completed in the 20th century following the origin design. It has two spectacularly ornamented towers, covered with arches, gables, pinnacles and openwork spires pointing upwards. The tower of Ulm Minster has a similar history, begun in 1377, stopped in 1543, and not completed until the 19th century.