Over many centuries Córdoba has experienced culture-altering invasions, each adding layer upon layer to the fabric of the town. A close look at the cathedral reveals a post-Roman Visigoth church which was converted to a Moorish mosque before a Baroque layer was added starting in the 13th century after the Spanish Reconquista. In modern times, yet another invasion is being laid down, with tourists adding (altering & subtracting) yet another layer.