The layout of the church has the shape of a Latin cross - with enormous dimensions. The Sagrada Familia is one of the world's largest Church buildings: from the entrance to the apse is 90 metres, the five naves are limited by a 60 metre long and 45 metre wide transept. The four side naves are 7.5 metres wide each, the main nave is 15 metres - exactly twice as wide. The vault of the main nave is 45 metres high, and the side aisles are 30 metres high.
Construction of the naves was started in 1987, based on models that were created by Antoni Gaudí, and which were not destroyed during the Spanish Civil War.
In the outermost naves, the chancels are both situated in a gallery. These provide space for over 1,500 singers.