Windmills used to be incredibly prevalent in the Dutch landscape, and more than 10,000 were used for industrial purposes. Later, they gradually disappeared as other sources were preferred, such as steam, then eventually diesel, and electricity. Every year in mid-May, the Dutch celebrate windmills with National Windmill Day. It’s a time of the year when they decorate the windmills with flowers, figures of angels, or Dutch flags. Kinderdijk is one of the best-known places for windmill watching. Its 19 windmills, almost all ‘grondzeilers’, are on the UNESCO world heritage list. These mills, which pumped up the polder water, played an important part in shaping the Netherlands. The Zaanse Schans is another popular windmill destination.