There's something mesmerizing about watching the blades of a windmill going around and around in the breeze. Check out Windmill to find out how these structures work.
You'll be spoiled for sightseeing choice in Delfshaven. Windmill is a good place to start here, but there are numerous other worthwhile sights to enjoy. Erasmus Bridge, Euromast, and Blijdorp Zoo are near the wind-driven milling structure and will fill in your day nicely.