Located inside of Casa Milà

Casa Milà was an urban apartment building designed by Gaudí. Taking up an entire city block in the fashionable Eixample district
with its pale wavy limestone facade and free form wrought-iron balconies, the Casa Mila is one of the most visited Gaudí
buildings after the Sagrada Familia.

This expressionistic architecture was completed in 1912 and doesn’t contain a single straight line. Ahead of his time, Gaudí
designed the Casa Milà without weight bearing walls and instead used steel arches and pillars in irregular shapes to
form the circular design. The wavy design looks like a living organic structure that embodies movement
and continuity.

http://www.gothereguide.com/casa+mila+barcelona-place/