The windmill originated in Persia in the ninth century. In the 12th century, knowledge of windmills spread to northern Europe as a result of the Crusades. A predecessor of the windmill was the windwheel, which the Greeks developed in the first century to provide energy.
The French, English and Flemish built the first European windmills. Other European countries that built windmills include the Netherlands, Germany, Denmark, Spain and Estonia. These counties used windmills for various purposes, such as grinding cereals or pumping water.
At one time as many as 200,000 windmills existed in Europe. The use of windmills declined as a result of the Industrial Revolution, during which steam power became favored over wind power. The Netherlands, which had 10,000 windmills in 1850, has around 1,000 left as of 2015. Few are in operation; the Dutch maintain the rest for historical purposes.
The Dutch used the sails of the windmills to convey signals. Traditionally, the miller was an important member of the community who used the windmills' sails to communicate news. Common signals included signs of celebration or mourning. Following the shooting of Malaysian Airlines Flight 17 in 2014, the Dutch tilted their windmills' sails in the mourning position in memory of the victims.