Rating: Not rated. Carved from a hundred million pounds of stone, soaring effortlessly atop a spiderweb of masonry, Gothic cathedrals are marvels of human achievement and artistry. But how did medieval builders reach such spectacular heights? Consuming the labor of entire towns, sometimes taking a hundred years to build, these architectural marvels were crafted from just hand tools and stone. Many now teeter on the brink of catastrophic collapse.