Tranekær Castle is Denmark's oldest inhabited manor, perched high on one of Langeland's distinctive hat hills with roots extending back nearly a thousand years, originally built by King Valdemar the Great around 1131-1182. The castle's red-plastered wings rise above a wide, still moat, with its current appearance shaped by a comprehensive 1859-1863 renovation designed by architect Niels Sigfred Nebelong. Continuously owned by the Ahlefeldt-Laurvig family since 1672, the castle remains in its 13th generation of family stewardship. While the castle itself requires advance booking for guided tours, the castle park and Borgsø lake are open to the public, with a walking trail offering changing views of this medieval and Renaissance masterpiece.