Landgoed Olaertsduyn (Olaertsduyn Estate) - Rockanje
This country estate, laid out in a historicizing style, was built in 1910 by architect Johan W. Hanrath for the Rotterdam shipowner William Smith. Leanord A. Springer is the designer of the garden. After the Second World War, a Volkshogeschool started using it well and several new buildings were erected on the site. During restoration in 1995 the sight axes were restored, the pond was dug and cleaned, and the path system was restored. The landscaping at the house has a more geometric character while it is more scenic further on. The park-like forest has a couple of streams. Many wild plants are found on Olaetsduyn. These tubers, bulbs and rhizomes are named after the Schierstins in Veenwouden, where they were first named by 19th-century botanists.