The Torre del Oro overlooked the Guadalquivir. It wasn't the highest tower ever, but there was also a small museum within it that made the trip worth it.
My favorite part of Seville was the Plaza de Espana. It was a beautiful park in the middle of a crowded city. I thought it was the perfect place to get away from the busy streets and enjoy the view of an amazing building. There were also boats on the small lake in front of the building, the spanish version of mini venice. Within the building, there were little symbols for every cities in Spain. My buddy and I didn't realize that the symbols were displayed in alphabetical order, so we ended up wasting 15 minutes walking and trying to find the symbol for Madrid.