This enormous church, as yet unfinished, is a summary of everything that Gaudí designed before. The structural difficulties he faced and errors he committed in other projects are revisited and resolved in Sagrada Familia.When designing the temple, Gaudí invented an extraordinary method for determining the correct angle for each of the leaning columns. He made a small hanging model of the church, using string to represent the columns. Then he turned the model upside down and... gravity did the math. The architectural style of Sagrada Familia has been called "warped Gothic," and it's easy to see why. The rippling contours of the stone façade make it look as though Sagrada Familia is melting in the sun, while the towers are topped with brightly-colored mosaics which look like bowls of fruit. Gaudí believed that color is life, and, knowing that he would not live to see completion of his masterpiece, left colored drawings of his vision for future architects to follow .

The church plan is that of a Latin cross with five aisles. The central nave vaults reach forty-five metres (150 ft) while the side nave vaults reach thirty metres (100 ft). The transept has three aisles. The columns are on a 7.5 metre (25 ft) grid. However, the columns of the apse, resting on del Villar's foundation, do not adhere to the grid, requiring a section of columns of the ambulatory to transition to the grid thus creating a horseshoe pattern to the layout of those columns. The crossing rests on the four central columns of porphyry supporting a great hyperboloid surrounded by two rings of twelve hyperboloids (currently under construction). The central vault reaches sixty metres (200 ft). The apse is capped by a hyperboloid vault reaching seventy-five metres (250 ft). Gaudí intended that a visitor standing at the main entrance be able to see the vaults of the nave, crossing, and apse; thus the graduated increase in vault loft.