A windmill can do many useful tasks, such as pump water, grind grain or generate power. The structures get part of their name from one of their most common uses: as mills for grain.
In this type of windmill, the wind caught in the sails of the device powers massive stones to grind wheat into flour. Similar mechanisms allow windmills to help pump water and drain land. The practical devices have been in use since at least the first millennium A.D. In 1890, Danish scientist Poul la Cour invented the wind turbine to generate electricity, and this invention is by far the most common use for windmills today, as many parts of the world are trying to shift from fossil fuels to renewable forms of energy.