Why locals love it
This architectural masterpiece, a fascinating combination of brick and oxidized iron, seems to hover in the air. It features a vertical garden and hosts several temporary exhibitions which run at the same time. It's a bargain as many exhibitions are free and others cost only 4 euros.
Why you should visit it
Just the building itself is well worth a visit. Don't forgot to check out the staircase and the café on the top floor. The exhibitions tend to be of a very high standard and encompass architecture, cinema, beauty arts, visual arts, etc.
After your visit you can have a rest in the Retiro Park, which is opposite the Caixa Forum.