Fairytale castle in Segovia
The Alcázar (from the Arabic al-qasr, meaning castle) is, after the Aqueduct, the premier sight in Segovia and has been built and re-built from everyone from the Romans to the Arabs to the Catholics, giving us a good overview of the history of Segovia. The castle itself is a whimsical, fairytale-like structure with point towers, a staggeringly deep moat, rocky bridges, and arched windows which inspire the imagination so much that even Walt Disney himself used the castle as a basis for some of his works.
When you enter, you have the option to visit the interior of the Alcazar as well as go to the top of the Juan II Tower, something I'd really recommend (unless you're claustrophobic...the winding stairwell is a bit tight). The interior of the Alcazar as throne rooms, royal bedrooms, and a hall of Kings, all of which are decorated with ostentatious roofs, red velvet, and mind-boggling tapestries.