The Catedral de Santa María de la Sede, Saville Cathedral, originally started out as a mosque built in 830 AD. This was later supplanted by a larger mosque completed in 1198. The Christianization of the mosque began with the conquest of Saville by King Ferdinand III in the 13th century. Building and remolding continued on and off for nearly 300 years. There are over 40 chapels within the cathedral. The Saville Cathedral is considered the third largest cathedral in the world and was designated a UNSCO World Heritage site. It has the longest nave of any Spanish cathedral. The current building reflects many types of architecture. The court yard built with the original mosque and enlarged by the later mosque is retained as part of the cathedral.
The most famous person buried in the Saville Cathedral is Christopher Columbus. His tomb is not easily missed.
The Giralda, bell tower, was originally built at the minaret for the mosque. It stands at 343 feet high with the bells placed on top.