Seville's Torre del Oro (Tower of Gold) was built in the 13th century during the Almohad dynasty to serve as a military watchtower. Today is stands proudly beside the banks of the Guadalquivir River and houses a small naval museum.
There are many theories behind the 12-sided tower's name, though it is thought to have come from the golden tiles that cover its dome, which may once have adorned the whole tower. By day it serves as a spectacular viewing point over the city.
The tower served as a prison during the Middle Ages, but today has the more modest role of naval museum, housing engravings, letters, models and military instruments. The tower also has a sister, the octagonal Torre de la Plata (Silver Tower) near Seville's old fortress.