Mills are industrial facilities that process raw materials into finished products. They often use machinery to grind, crush, or refine materials like grains, metals, or wood. Common types of mills include flour mills, which produce flour from wheat, and sawmills, which cut timber into lumber. Mills have played a crucial role in the development of economies by enabling mass production. They can be powered by various energy sources, including water, wind, or electricity. The invention of the water mill in ancient times significantly advanced agricultural and industrial practices, leading to increased efficiency and productivity.