Casa Milà (La Pedrera)

Gaudí built it between 1906 and 1912 as an apartment block for the Milà couple. Locals mockingly nicknamed it «La Pedrera», the quarry, for its undulating stone façade without a single straight line and its seaweed-like wrought-iron balconies.

The visit covers the roof, with chimneys and stair exits like helmeted warriors; the attic, with brick arches like a whale's skeleton; and an apartment furnished as in the early 20th century. It has been a World Heritage Site since 1984.