It’s a world wide symbol of Barcelona. The monumental church El Temple Expiatori de la Sagrada Família (Expiatory Temple of the Sacred Family) is Gaudí's most famous work and the finest example of his visionary genius. The architect undertook the task in 1883 on the site of a previous neo-Gothic project begun in 1882 by F. del Villar. Gaudi dedicated his life to carrying out this ambitious undertaking which due to his sudden death was left unfinished.
Gaudí became obsessed with the church to the point that not only did he focus all of his creative energies into it, but he set up residence in his on-site study as well. On June 7, 1926, Gaudi was hit by a street car while crossing the Gran Vía at Gerona. Three days later not having regained consciousness, Gaudí died at the age of 74.
Work continued on the church, however, until it was interrupted in 1936 when the crypt and Gaudí's study holding his notes and designs were burnt by Spanish Civil War shelling. The project was resumed in 1952 using drawings and scale models as a base although the continuation of the work gave rise to much debate. From 1954 to 1976, the facade and the four towers of the Passion (Western side) were completed. The sculptor Josep. M. Subirachs joined the project team to work on the sculptures on the Portal of Passion in 1987. Today, the constructed part is open to visitors as well as the small Museu del Temple Expiatori de la Sagrada Família with scale models and drawings showing the construction process. 

Gaudí's patron, Eusebi Güell, planned a suburban "city." His property was high above Barcelona, northwest and some distance from the city. More than 60 housing plots were allocated although only two homes were built on the property. The project was radical for its time and, as a real estate project, was a failure. The Barcelona City Council bought the property in 1922 and in the following year converted it to a municipal park.
Gaudi avoided levelling the grounds so that the park has a network of twisting roads which follow the contours of the land,  the lowest point is the entrance.