TL;DR
Construction began in 1882, stalled after Gaudí's death in 1926, was severely set back by the Civil War in 1936, resumed slowly through the mid-20th century, and has accelerated dramatically since the 1990s. Computer-aided design has transformed what's possible. More has been built since 2000 than in the first 80 years combined. The building is projected to be substantially complete around 2026–2030.
Crypt completed (1889). Apse completed (1893). Nativity façade largely complete. Gaudí devotes himself entirely to the project from 1914.
Work continues under architect Domènec Sugrañes using Gaudí's surviving models. Nativity façade towers progressed. The project struggles for funding.
Anarchist militia burns the crypt, destroys Gaudí's studio and workshop, and sets fire to his plaster models. Much of his original documentation is lost. Construction halts.
Architects painstakingly reconstruct Gaudí's vision from photographs, surviving fragments, and geometric principles. Construction resumes but proceeds extremely slowly.
Computer modelling validates and extends Gaudí's geometric systems. The Passion façade is begun (1954) and Subirachs starts the sculptures (1986). Construction accelerates significantly.
UNESCO World Heritage Site designation (2005). Pope Benedict XVI consecrates the basilica (2010). The central nave is completed (2010). Tower construction accelerates. Cranes are a permanent fixture.
Tower of Jesus Christ begins (2021). Major tower completions. The Glory façade portal begins construction. The building in 2025 is more complete than at any previous point in history.
The Civil War and What Was Lost
The night of 20 July 1936 was the most damaging in the building's history. Anarchist militia attacked the crypt, burned Gaudí's workshop, and destroyed the plaster models he had spent decades perfecting. The workshop fire lasted several days. When it was over, roughly 70 percent of Gaudí's surviving design documentation had been lost.
What survived came from multiple sources: photographs taken during construction, geometric principles Gaudí had published and described in writing, fragments of plaster models recovered from the ruins, and the memory of architects who had worked directly with Gaudí. The painstaking reconstruction of his vision from these scraps took decades and is itself one of the great acts of architectural scholarship of the 20th century.
How Modern Technology Changed Everything
The shift from hand calculation to computer modelling in the 1980s and 1990s transformed what was possible. Gaudí's geometric systems, based on paraboloids, hyperboloids, and helicoidal surfaces, were perfectly suited to computational modelling. What had taken Gaudí years of physical experimentation with hanging chain models could now be validated and extended digitally in months.
The Barcelona-based architectural firm currently overseeing the building has used parametric design software to generate and verify every surface on the remaining towers. The result is construction that Gaudí would recognise as his own because it proceeds from his geometric principles, even where his specific drawings no longer exist.
Stone is now pre-cut off-site using CNC machines programmed from the digital models. Work that once required master stonecutters working by hand for months can now be completed in weeks. This is why more has been built since 2000 than in the previous eight decades combined.
Key Milestones at a Glance
| Year | Milestone |
|---|---|
| 1882 | First stone laid, 19 March |
| 1883 | Gaudí takes over as chief architect |
| 1889 | Crypt completed |
| 1893 | Apse completed |
| 1926 | Gaudí killed by tram; Nativity towers incomplete |
| 1930 | Nativity façade towers completed by collaborators |
| 1936 | Civil War fire destroys workshop and most plans |
| 1954 | Passion façade begun |
| 1978 | Passion façade towers completed |
| 1986 | Subirachs begins Passion façade sculptures |
| 2000 | School of Gaudí restoration completed |
| 2005 | UNESCO World Heritage Site designation |
| 2010 | Papal consecration by Benedict XVI; nave complete |
| 2021 | Virgin Mary tower completed; Jesus Christ tower begun |
| 2026 | Centenary of Gaudí death; Jesus Christ tower projected complete |