Molen Van Sloten. In Sloten, just outside of Amsterdam.
The #2 tram takes you most of the way there (the 68
bus takes you the rest of the way if you don't want to
walk). At the corner of Akersluis and Langom. The
only one of the mills I found that you could go in and
get a tour of. It's also an operating mill, pumping
water out of Sloten and Amsterdam into the Ringvaart,
to be dumped into the North Sea at low tide. While
they let the blades run when open, they only engage
the Archimedes screw when the water level is high
enough. Alas, the water level wasn't high enough when
I visited.
You can also see the mill from the airplane. I took a
picture (the third time I saw it from the air), but
only had an 80mm lens. It's much easier to spot from
the plane than it is in this picture.