The Dutch have had a complicated relationship with the water that surrounds them, from the earliest days of settlement in the Delta- a place often considered completely unsuitable for human habitation. The Dutch have evolved an immensely sophisticated system to separate land and water. Rivers in Holland rarely get their way- allowing them to run freely is dangerous because so much of the land is below sea level. Many of the windmills that still dot the landscape were originally put up in the 17th century to be used as large water pumps, to mill dry land at the bottom of shallow lakes and bays. Most of the Netherlands would be under water otherwise.