Okay so after reading all of your comments, I think that I am the only one who is actually from Spain here. So, Gaudi style is present in the city of Barcelona, maybe some old lady has some of his art at her house but that is it, regarding the arquitecture, Gaudi´s influence is extendable to barcelona and some other parts in cataluña. (yes, I have the ñ in my keyboard).
I guess that Oda wants to show various different arquitectural styles that are present in Spain. Appart from cataluña, we have also seen buildings which look pretty similar to those in the south of spain (in andalucia, where seville and marbella are). These were shown when Oda drew the place where Doflamingo and his crew are. So, what are we missing? Well, I am from Valencia, so maybe we get to see some palm trees close to Green Bit, and I also think that he will show us some of the typical mills and long fields from castilla la mancha (placed in the center of spain)
Aaah one thing I forgot, The landscape of where the sunny is anchored is typical from Galicia (north of portugal) where we get most of the sea food and shellfishs here in Spain from so that is that. It is also possible for him to include some bull races like those in pamplona when the san fermines are taking place or some burning of giant structures like we have in valencia in fallas (which are happening now)
That´s all there is here folks!
You forgot the castles! We have already seen them in the city they arrived. They are typical from Catilla y Leon, where I am from. I am really eager to see what Oda will do with the Spanish culture =)