Gaudí was asked to continue the construction of the cathedral in 1883, after Francesco de Paula del Villar gave up the project due to its differences with the foundation of the temple. Gaudí spent almost all his professional life in this project until he tragically died after being run over by a tramcar, when he was 74 years old. He left the Neogothic floor and gave it his own personality.

Most of the aspects of his architecture were defined when the building made progress, so that was why its presence in the building site was indispensable. As the façade of the Birth advances his style becomes more fantastic. There is glass from Murano in its peak; moreover, there are several decorative elements in the towers that some people consider they come from the Art Nouveau. He only completely finished the Saint Joseph´ s chapel, the crypt, the external apse and the façade of the Birth.

The four towers are culminated by crosses oriented to the four cardinal points, where the sculpture and the colour are joined with the word in order to get an organic union, alive, of the nature with the target of praising God made man. When Gaudí died, the construction continued and was based on the scale models and designs made by the master. The rest of the façade was completed in 1935.

The West façade, the Passion, was built between 1953 and 1976. The sculptor Subirachs was asked to decorate this area. The construction of this great building continues today.

The temple shows the global conception of the architecture, where plastic, natural forms, symbolism and colour create a unique and genuine mosaic. The building has a Latin cross plan with 5 naves and a transept of 3 naves. The outer cloister links the three façades: Passion, Glory and Birth, with each one of the four bell towers.