Click on the ENGLISH icon and read all about Kinderdijk. Absolutely MIND BLOWING! (no pun intended) :-)
Some information from the website to give you an overview:
The Netherlands is famous for its windmills. Today there are still more than 1.000 mills. Nowhere in the world you will find as many windmills as near (the Dutch village) Kinderdijk. Around 1740 no less than 19 sturdy mills were built here. They have been well preserved to the present day.
The mills drain the excess water from the Alblasserwaard polders - which are situated below sea-level - after which the water is sluiced into the river Lek (the Rijn).
The powerful mill sails serve to transmit the force of the wind on to large paddle-wheels which scoop up the water. Nowadays power-driven pumping engines do the job, including one of the largest water screw pumping-stations in Western Europe.