The Giralda is a former minaret that was converted to a bell tower for the Cathedral of Seville in Seville. The tower is 104.5 m (343 ft) in height and it was one of the most important symbols in the medieval city. The tower was begun under the architect Ahmad Ben Baso in 1184 (...) (from Wikipedia).
The Giralda Tower, adjacent to the cathedral, is a Moorish Tower, and is considered the city's most recognizable landmark. It was constructed as early as the 12th century, and later additions were built in the 16th century. A climb to its top is worthwhile, although difficult. You can enjoy a wonderful view of all of Seville from the top.