Berkswell Windmill, West Midlands, England.
A windmill is a wind energy conversion system (WECS) that is used, among other purposes, to grind grain, and that typically has a high-solidity rotor; the term "windmill" is often used to refer to all types of WECS. Windmills have been used by humans since at least 200 BC for grinding grain and pumping water. The idea spread to Europe in the Middle Ages. Their use was widespread during the early years of the Industrial Revolution, but declined with the development of the steam engine in the 19th century.
By the 1900s, windmills were used on farms and ranches in the United States to pump water and, later, to produce electricity. Traditional windmills have more blades than modern wind turbines, and they rely on drag to rotate the blades.