Gothic Cathedrals, these skyscrapers of stone dominated skylines for nearly a thousand years. Their revolutionary design made it possible for builders to erect walls almost entirely of glass that support multi-ton ceilings of stones. How, without the benefit of modern tools and technology, did medieval builders construct Gothic Cathedrals. Now, an international team of experts investigates how they were built, and why some of the tallest ones fell down. Embedded in stone and stained glass, they uncover a hidden mathematical code -ripped from pages of the Bible - that used as a blueprint to build the great Gothic Cathedrals.