There is something mysterious about cranberries. People have their secret places where they pick this sour berry and they don't readily tell others. The cranberry is especially known from Terschelling; however it also grows in the dunes on other Wadden Islands, and occasionally along the shores of the mainland. When it was discovered in the 19th century, botanists thought that it was a resurrection of an indigenous heath species. But in reality it is native to eastern North America. Cranberries grow is nutrient-poor damp (dune) slacks and peat grounds. Although Terschelling is famous for its cranberry pie, jam and syrup, most berries are presently harvested on Vlieland.