The lowlands of the Netherlands were flooded until the Dutch began building dykes (low dams) and draining the water out with windmill pumps for farmland. Because much of this land, called polders, is below sea level they have to keep pumping all the time.

When three or more windmills work together, it is called a "molengang". A "3-gang" or a "4-gang" is used when the difference between the water in the polder and the water around the outside of the polder is too much for one mill to handle. Then the water is removed from the polder in steps.

This drawing could only be of one country in the world. The windmill standing behind the tall thin houses look very typical of the Netherlands.

Why do you think that in Dutch cities, the houses are often extremely tall and thin?