Humans have used pools and still waters for viewing themselves for centuries; later, polished metals and volcanic glass were used as mirrors. Evidence suggests the sheet of glass, backed with metal, was invented in Lebanon 2400 years ago, where the glass was also invented. But the silvered-glass mirrors we found today everywhere were invented 200 years ago in Germany. In 1835, chemist Justus von Liebig invented applying a thin layer of metallic silver to one side of a pane of clear glass. His invention was adapted and improved for the mass production of mirrors. His patent No. 38,721 was granted on November 12, 1861.