Friends of ours had been to the castle previously and had enjoyed the castle and tour of the courtyard but had not done the palace tour. To obtain access to the Palace, you must upgrade to the Palace tour which is a 4 euro upgrade on the basica admission of 7 euros.The tour of the palace makes the day more worthwhile and they offer several languages/tours during the day. Our tour guide had a dry wit and made the day much more enjoyable. You also learn a fair bit about the protestant church and royal families including the British family. You can walk about the castle once the tour is down and spend some time in the Apothecary museum as well as the world''s largest wine barrel.