This document summarizes several important monuments in Spain, including the Cathedral of León, the Aqueduct of Segovia, La Alhambra in Granada, the City of Arts and Sciences in Valencia, the Sagrada Familia in Barcelona, the Mosque–Cathedral of Córdoba, La Giralda in Seville, and several castles across Spain. The monuments showcase different architectural styles ranging from Gothic to Islamic and date from Roman times to the modern era. Many are UNESCO World Heritage Sites and among the most visited sites in Spain.