Solid and determined—having withstood the sieges of time, revolution, and war—the cathedral's stumpy facade is stuck almost bashfully onto the nave. Although the mishmash inside has its moments—the fabulous 13th-century stained-glass windows in the choir and the varied window tracery and vaulting in the side chapels—the interior lacks drama and harmony. Still, it's an architectural history lesson. The cathedral dates from the 12th century, and the chancel is Romanesque, but construction on the whole continued over three centuries. The 14th-century astronomical clock, in the north transept, is a marvel of technology very much worth seeing. It chimes a hymn to St. John on the hour at noon, 2, 3, and 4 as a screeching rooster and other automatons enact the Annunciation.