The expiatory church of La Sagrada Família is a work of grand scale that was started on March 19th, 1882, based on a project of the diocesan architect Francisco de Paula del Villar (1828-1901). At the end of 1883 Gaudí was commissioned to carry on the work, a task which he did not abandon until his death in 1926. Since then, many different architects have continued the work after his original idea.
The building is located in the centre of Barcelona, and through the years, it has become one of the most universal signs of identity of Barcelona and Spain. It is visited by millions of people every year and many more study its architectural and religious content.
It has always been an expiatory church, which means that since the outset, 125 years ago now, it has been built from donations. Gaudí himself said: “The expiatory church of La Sagrada Família is made by the people and is mirrored in them. It is a work that is in the hands of God and the will of the people.” The building is still going on and could be finished some time in the first third of the 21st century.
(taken from http://www.sagradafamilia.cat).