It's a 19th-century Dutch `beltmolen` with a brick base and wooden cap.
The Royal Roermond Windmill exhibits the characteristic architecture of a 19th-century Dutch `beltmolen`. This style features a substantial brick base built upon a natural or artificial mound (``belt`"). The brickwork provides a sturdy foundation. Above the base sits a wooden, rotating cap which houses the main machinery and allows the sails to be turned into the wind. The sails themselves are typically a traditional Dutch design, made for efficient grain grinding.