Trencadís and the art of reuse
On the rooftop of Casa Milà you can find these ventilation ducts and chimneys, some of which are decorated with the famous "trencadís" technique (from the catalan word "trencar", which means "to break").
In other places like the Park Güell, Trencadís was used for the undulating bench, and was done mostly with the leftovers of glass and ceramics. Gaudí wanted to reuse the things that was left behind by other people. This might be considered as one of the first ecological art creation.
From this rooftop of Casa Milà you can enjoy some of the most beautiful views of the Eixample.