Aerial view of the historic Castillo de San Marcos in St. - The Castillo de San Marcos is one of St. Augustine's biggest attractions, and the oldest structure in the entire city! I enjoyed all the sights and shopping in St.
Castillo de San Marcos (Castle of San Marcos or Castillo de Alfonso X El Sabio), medieval castle located in El Puerto de Santa María, Cádiz, Spain. The castle was erected as a fortified church by King Alfonso X of Castile. It was built on the site of a mosque of which the wall of the qibla survives. 12th century. #Spain