Walls and Towers - Copper is an Empire Earth technology found in the Copper Age. It is researched from the Town Center or Capitol. It costs 50 Stone and it increases the Towers Hit points by 450, from 1000 to 1450 Hit points. It takes 45 seconds to research this technology. Every civilization in the game has the ability to develop this technology. Do note that this DOES NOT upgrade the Walls Hit points.