Metal casting has a long history dating back over 5,000 years when the earliest known casting, a copper frog, was created in Mesopotamia in 3200 BC. Since its discovery, metal casting has played a critical role in advancing human civilization and is now more essential than ever in our everyday lives. Some key developments in metal casting over time include the discovery of iron in 2000 BC, the first production of cast iron in China around 800-700 BC, and the invention of sand molding in 645 BC. Modern innovations include semi-solid metalworking in the early 1970s, vacuum molding developed by the Japanese in 1971, and electromagnetic casting processes developed in 1997.