The Duomo or Cattedrale dell'Assunta hosts very fine paintings by the most renowned artists of the period, while the octagonal bell tower standing over the ancient crypt with the same octagonal shape points to the sky. Both dominate the landscape as you view Pienza from afar. As you walk through the church you will notice the uneven floors, the unsettling cracks making their way across the paviment and little glass plates (like lab slides) glued to the walls. The architects didn't calculate the effect of the weight of the cathedral and its impact on the foundation of the church and now the hillside that it is built on is starting to "give way". The little glass plates are a way of controlling the shifting of the earth and the structure....everything is fine....until one of them cracks!