Molen de Roos is the only remaining windmill of the 18 that once operated in Delft, built in 1679. This stone tower mill is still operational today, grinding organic grain into flour every week powered by wind. Visitors can climb four floors, learn about traditional milling techniques from volunteer guides, and enjoy panoramic views over Delft's rooftops. It features a beautiful garden and seasonal cafe serving bread made from the mill's flour.