Casa Mila La Pedrera is one of the amazing creations by Antoni Gaudi an architect responsible for many of the amazing creations that have become a legacy for the city of Barcelona. This building he designed for a couple who wanted to live in but they had the vision of renting out rest of the floors to tenants. Even today there are actual residents living in this building and you only have access to one of the floors and roof.
However the design inside and outside are very impressive for the period when these were built. Definitely worth a visit!!