The ’Molen van de Horn-en Sommeerpolder’ is a windmill located on Stommeerkade in Aalsmeer. The mill is no longer in active use, but visitors can learn about how mills were once used for a variety of purposes, including grinding grain to make flour, and draining the land of water to create polders suitable for human habitation. Wind mills would power pumps to drain water from the land, and direct it to canals and rivers nearby.