This probably goes without saying, but I found Salamanca to be one of the most enchanting places I've visited in Spain, let alone the world. I studied for 2 weeks in the summer of 2001 there, and had the time of my life. If I were to move back to Spain, it would be my second choice behind Madrid. The Plaza Mayor may very well be the best in all of Spain, the food is distinctly Castilian, and the people and atmosphere is marvelous. It is quite reknown for it's international ambiance, with students from all over Europe and North America attending the University. The architecture is unique: I've never seen anything quite like it. The sun seems to glisten off of it. It does get pretty damn hot in the summer, so be prepared, but also get ready to enjoy yourself immensely.