They have free guided tour during the day. When I say free, it's literally free. A guide will explains all the history and take you to cool facilities. I don't t think it's often that you get to see all the important court rooms. And when I went there with a friend, there were just us so it was like a private tour. The only reason that it is 4stars instead of 5 was that it was all Spanish but it's worth visiting anyway.