Construction began in 1892. A portion of the temple called the Nativity Facade was completed in 1925. Gaudi died in 1926. However, his design was continued. The temple building with five naves, and three facades around the center apse is still under construction. Construction has been halted a few times due to lack of money to continue. Today though, the temple is an important tourist destination and that provides enough funding to complete the structure. Experts believe it will be completed about 2028.
The main walls and ceiling of the church are supported by catenary arches, which are very strong. This allows free standing sides and facades of intricate carvings because they do not need to support the building.