Castle of San Marcos is a 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.
Close to the castle there is a replica of the map of Juan de la Cosa, along with an explanatory plaque; and a little fountain.
Wikipedia https://en.wikipedia.org/wiki/Castle_of_San_Marcos_(El_Puerto_de_Santa_María)
Address 2 Plaza de Alfonso X 'El Sabio', El Puerto de Santa María 11500, Spain
Coordinates 36°35'47.111" N -6°13'35.866" E
