This is the exterior of Casa Batllo, Barcelona, an apartment building designed entirely by Gaudi and considered his masterwork. Inside Casa Batllo is just as amazing. A wonderful, incredible example of Nouveau free-flowing style, exquisite stain-glass windows, beautiful woodwork and ceramic decoration. The degree of detail and design has to be seen to be believed. Every single aspect of this building is conceptual right down to the buttons on the elevator panel. And check out this picture of Gaudi’s skylight design! Casa Mila [also known as La Pedrera – or The Quarry]. It was built for the married couple, Roser Segimon and Pere Milà. Roser Segimon was the wealthy widow of Josep Guardiola, an Indiano, a term applied locally to the Catalans returning from the American colonies with tremendous wealth.