The 19 windmills of Kinderdijk were built around 1740. Their purpose was to pump the excess water into a reservoir until the level of the river had reached a level that pumping the water into the river (called the Lek) was possible again. Since 1927 a diesel pumping station does the real job. The windmills were used for the last time during the second World War, when the mechanical pumps could not be used any more due to fuel shortages.