Hospital de Sant Pau

A fully functioning hospital until 2009, Hospital de Sant Pau has been transformed into a museum and cultural center that holds over six centuries of Catalan history. For architecture fans, the colorful and bright Art Nouveau structure (the world's largest) is a must stop. While the surrounding area is often overrun with tourists who come to see the nearby Sagrada Familia, the Hospital is a lesser-known gem without the lines or crowds.