Rapperswil Castle stands on the rocky hill at the centre of the peninsula, its three towers rising above the old town rooftops. Built in the early 13th century, it is a compact square structure with a courtyard and a well-preserved great hall. The grounds around the castle offer some of the best views of Lake Zurich — east toward the Etzel hills and west toward Zurich itself.
The castle currently houses the Polish Museum, which traces the long relationship between Switzerland and successive waves of Polish exiles. The collection includes manuscripts, documents, art works, and memorabilia relating to the failed uprisings of 1830 and 1863, and to the Polish community that settled in Switzerland as a result. It is a serious and well-curated institution in an unexpected setting.