- Metal Ages (Wikipedia)
The Metal Ages is a term for the period of human civilization beginning around 6,000 years ago in which metallurgy rapidly advanced and human populations started using metals such as copper, tin, bronze and finally iron, to make tools and weapons. By heating and shaping metals in hot furnaces, people also learned to use precious metals such as gold and silver to make intricate jewellery.
Shadows on the SR 520 Trail