This stuff really interests me from an architecural perspective thanks to Buckminster Fuller, but even more interesting is the deeper and deeper you look into this, it begins to show up everywhere; nature, religion, art, anatomy, science, cosmology to the more esoteric fields of mandalas, chakras, crop circles and freemasonary. Some links to get you hooked;

Sacred Geometry Explained on Youtube

Introduction to Sacred Geometry

Sacred Geometry: The Architecture of the Universe