Damascus Steel Blades
300–1750 CE
Damascus steel blades, produced from Indian wootz steel between 300 and 1750 CE, were legendary for their ability to hold a razor-sharp edge while remaining flexible enough not to shatter. The distinctive watered pattern on the surface was not understood until 2006, when researchers discovered the blades contain carbon nanotubes — a nanostructure not officially discovered until 1991.