Casa Milá

We head to Paseo de Gracia and La Pedrera, oficially known as Casa Milá. It is a huge structure framed in steel with wavy forms of stone and concrete hung from the frame. It is an apartment building with businesses on the ground floor. The tour is: look at the outside,

climb to the roof and check out the chimneys and the view,

descend through the attic (a museum of history of Gaudí) and tour one of the apartments.

Gaudi used caternary arches to lighten and open up otherwise tight spaces. Much of his innovation in architecture came from observations of shapes in nature such as this viper skeleton.