In an article in the Atlantic, glass was called humanity's most important material. In order to connect you and me, writes Douglas Main, these words are encoded into optical signals that travel at 300, 000 kilometers per second through fiber-optic cables, across mountains, underwater, across cities and countries, and across the globe. The glass inside these cables is thinner than a human hair and 30 times more transparent than the purest water. Glass allows us to see and be seen, to hear and be heard, to light up our rooms, our lives and our thoughts.