Buttresses are the key to Gothic art. Thanks to their support, church naves are able to reach for the sky. The master builders devised high walls, slender buildings, openwork volumes, and aerial pinnacles. High windows as well, which allow natural light to enter the churches. The major period of the Gothic style begins in the 14th century, during which ornaments and decorations were pushed to the limit. The abbey of Mont-Saint-Michel was transformed into a true work of art.