Science boffins shouldn't miss this museum of marvels inside the elegant Orangerie building. After passing Foucault's pendulum, which topples a pin every ten minutes, there's a room dedicated to navigation and astronomy, with sextants, ancient telescopes and other instruments to try out on a reconstructed balcony of Kassel's Stadtschloss palace, which was Europe's first modern observatory. Another hall is dedicated to timekeeping, going from sundials and hourglasses to early digital machines and atomic clocks. Ask the attendants to set the huge old clock from St Martin's church in motion. Pride of the collection is the gobsmacking Augsburger Prunkuhr clock from 1680, encrusted with gems and moving figures, with a little Kugelbahn circling the top. Fans of late Baroque and Italian art should ask to be shown the adjacent Marmorbad ('marble bathhouse'), filled with Carrera marble sculptures by Pierre Monnot who worked in Kassel for 15 years. Finish off your visit by following the 3km 'planet walk' through the park, representing the 495 million kilometres to the edge of our solar system, with all planets sculpted in proportion to the sun painted above the museum door.