Ever wondered how the Dutch handle all the water in their lowlands without getting flooded? Me netiher. But I love those Dutch windmills. If you like them too, then you might want to visit Kinderdijk, the location of a set of historic windmills, that are protected as UNESCO World Heritage. There are 16 of them to be exact, built in the 18th century and kept in the original state.
While the area around it isn't the most exciting one (and water management admittedly doesn't sound too sexy either), the windmill park is well worth a day trip. You will only need tickets if you want to visit the windmill museum: walking or cycling around the park is free.
While there are quite a few eating places around, we went for a quick snack around the corner. We found an uitsmijter (fried egg on bread with ham & cheese) quite tasty and sufficient as a snack. For more culinary experiences, you might want to drive to Belgium ;)