You can see how big and empty Spain is by taking an evening train to Zaragoza. Minutes pass by, even though the train travels at 300 km/hour, without even a single light in the horizon – if there were roads, they had neither streetlights nor traffic, and if there were houses, then nobody must have been home. The occasional gas station was the only indication that the (very smooth) train wasn’t inside a tunnel.
While Zaragoza itself isn’t considered a major tourist destination, it has a few sights worth seeing. The Palacio de Aljaferia in Zaragoza is absolutely amazing. Everything, from the Moorish plaster doorways to the deep moat (the palace became a fortress after the Moors were expelled) was astonishing to me (and the free entry on Sundays was nice). However, since I only had a Sunday to see the city, I wasn’t able to visit either the Zaragoza Museum nor the Goya Museum due to their limited Sunday hours. As for the Cathedral of Our Lady of the Pillar, while it was interesting to see some of the unexploded bombs thrown at it during the Spanish Civil War, I’m still bitter that the one euro coin I placed into the illumination machine did not in fact illuminate the Goya painting in one of the chapels. Oh well.