Historically, windmills in Holland served many purposes. The most important was pumping water out of the lowlands and back into the rivers beyond the dikes so that the land could be farmed. In the fourteenth century, hollow-post mills were used to drive scoop wheels to drain the wetlands. Windmills transfer wind energy to rotation energy by catching the movement through wings that are sent spinning. This movement is then used for all kinds of work, from pumping water and grinding corn, to creating electricity. The best tulip fields are in the North of Holland, around 30 minutes drive from Amsterdam, in an area known as the bollenstreek (bulb district). Many fields are located behind the North Sea dunes and are therefore in a very scenic location.