The medieval capital of Castile naturally merited a suitably grand cathedral, and the Santa Iglesia Basilica Catedral Metropolitana de Santa María de Burgos is without a doubt one of Spain's grandest. Started in French Gothic style and consecrated in the 13th century, it took some 300 years to complete, adding Plateresque and Renaissance embellishments in the process. It's the only Spanish cathedral to be listed independently as a UNESCO World Heritage Site. The interior is grand, as well, with various impressive altarpieces, stained glass, and and the tomb of El Cid, the legendary medieval hero of the Reconquest.
It's one of Tripatini member Shiv's 8 Gems among Europe's Lesser Known Cathedrals and Churches.