I live (like many other Dutch people) in a polder, from Wikipedia:
A polder is a low-lying tract of land enclosed by embankments known as dikes, that forms an artificial hydrological entity, meaning it has no connection with outside water other than through manually-operated devices. There are three types of polder:
Land reclaimed from a body of water, such as a lake or the sea bed.
Flood plains separated from the sea or river by a dike.
Marshes separated from the surrounding water by a dike and consequently drained.The type of polder I live used to be marsh land. Around 1300-1400 this area was colonized. This means dikes had to be build and canals dug. First they relied on draining methods of the Romans but somebody invented the windmill! The wind mill you see is from 1400, the basement. It got destroyed in a war in 1600 and was rebuild directly afterwards.
Now a days the draining is done automatically, but at times the ‘Ministry of Water State’ asks to the mill to join in. There is more heavy rain then there used to be. In fact the mill would be sufficient for this polder because it is strong and capable of transmitting large quantities of water.
Mills are now usually run by volunteers. The mills themselves are kept by the state, they cost a fortune but are considered valuable landmarks. Holland is so stuffed with old stuff, if you like history it is worth a study. It would take a life time to learn about it.