Schloss Rapperswil, perched on a rocky promontory extending into Lake Zurich, commands the surrounding area, encompassing the town below. Built between 1220 and 1230 by Vogt Rudolf von Rapperswil, it oversaw vital water routes and pilgrimage paths. Ravaged during the Thirty Years' War, it was later rebuilt, serving various purposes, including a prison. Acquired by Wilhelm I. of Württemberg in 1858, the ruins transformed into a Moorish-style villa. The castle's history includes the failed Zürich coup of 1336 and a pivotal role in Swiss history. Today, it houses the Polish Museum, a testament to the enduring Polish-Swiss friendship. The castle's current triangular layout, featuring towers at each corner, dates back to Albrecht II.'s reconstruction. Notable towers include the Bergfried, Zeitturm, and Pulverturm, while the Polenmuseum reflects a rich cultural heritage within its walls.