Kinderdijk is a cruise port located at the confluence of rivers Lek and Noord in Netherlands (Molenwaard municipality, South Holland province). It is approx 15 km (9 ml) east of Rotterdam. A system of 19 windmills was built in 1740 to drain the polder (Alblasserwaard). These authentic windmills are among the best-known tourist attractions in Holland, and since 1997 are designated UNESCO Site.
In this polder, problems with water drainage became more serios in the 13th century. Then large canals had to be dug to drain out the excess water from the land and in the polders. Later was decided to be build a series of windmills to pump the excess water into a reservoir at an intermediate level between the polder and the river. Although some of these 3 centuries old windmills are still used, the main waterworks are provided by diesel pumping stations.