La Pedrera

Also known as Casa Milà, La Pedrera may be Gaudi's most renounced masterpiece - well, after Sagrada Familia, probably. Although, in my personal opinion, La Pedrera is a bit overrated (when compared to Casa Batlló for instance) it's still an impressive structure in its own right. Likewise, La Pedrera is located on Passaig de Gracia too, a short walking distance from the rest of the typical Gauidi material. 

After some point you start naming what's Gaudi and what's not, anyway :)