Located about one hour by train from Madrid is one of the best locations for a daily trip. The town itself is absolutely great not only the old town. When i first saw the aquaduct as it pop-up behind a house i was really surprised and amazed. It is something nonforgetable. Walking just around the small streets of old town will give you the real sense of history. Catherdral from outside looks like from a fairy tale.
Please dont miss the Alcazar which is small as it is a former castle on a steep rock, but it is very interesting and very nicely decorated. For military fans there is a small exhibition of artillery.