We travelled with Janneke to Kinderdijk, which boasts a remarkable collection of working windmills constructed many years ago to pump water from the fields. As we arrived (on a very cloudy day), people were beginning to unfurl cloth sails on the arms which then began turning - quite a bit faster than we expected. These are fascinating structures. Their entire tops must be turned to face the wind if it changes, and that is done by a large boom that extends to the ground (photo 5).