Nice site. We expected little more than an easy Sunday afternoon walk along the water with some mills in the background.
However, if you buy a ticket a short film in the 'gemaal' (the machines taking over the role of the mills) explains the functions of the mills and you can visit two (working) mills.
One mill can be visited from bottom to top while the other is limited to the ground floor. This gives an interesting insight in the lives of the millers anf their families. In both mills also a guide is present explaining the mill mechanics.
Interesting site around what the Dutch do best, i.e. water management.