Tin is a white metallic element that people have used since ancient times. The earliest known use of tin occurred sometime after 3500 B.C. in the Zagros Mountains of what is now western Iran. The people of that region made such articles as weapons and tools from bronze, an alloy of tin and copper. Today, tin is used chiefly in the production of tin plate. Tin plate consists of steel coated on both sides with an extremely thin film of tin. Most tin plate is made into tin cans.