La Sagrada Familia (or Church of the Sacred Family) is the most visited place in Barcelona and is Antonio Gaudi's most famous work. It is a work of immense proportions and is revered by the World of Architecture as one of the most original and ambitious modern buildings. As you can see the building is still under construction and won't be completed for another 80 years, even though construction started on the Sagrada Familia in 1882.