On the surface of Bornholm older geological formations can be seen better than in the rest of Denmark. Stubbeløkken - which is still operating (Danish i drift) - and Klippeløkken granite quarries in Knudsker parish just east of central Rønne - and statistically a part of the town - are among the few remaining quarries of what was once many active quarries on the island. The island's varied geography and seascapes attract visitors to its many beauty spots from the Hammeren promontory in the northwest to the Almindingen forest in the centre and the Dueodde beaches in the southeast. Of special interest are the rocky sea cliffs at Jons Kapel and Helligdomsklipperne, the varied topography of Paradisbakkerne and rift valleys such as Ekkodalen and Døndalen. Bornholm's numerous windmills include the post mill of Egeby and the well-kept Dutch mill at Aarsdale. The lighthouse at Dueodde is Denmark's tallest, while Hammeren Lighthouse stands at a height of above sea level and Rønne Lighthouse rises over the waterfront.