Sagrada Familia(Barcelona)

it would not be an understatement to say that this the world's most famous construction side. This was supposed to be a simple church built by another achitect but the city found the old design too plain. so they commisioned Gaudi to built a new church to replace to old one. This is Gaudi's unfinished work, as work started in 1883 but they were unable to complete it in the lifetime of Gaudi. (work is still ongoing at the moment, there are approximately 20-30 ppl working on it daily) the expected year of completion is in 2020 but then with the progress as such, the date could even be pushed back even further. Gaudi managed to finished the plans for the church but subsequently died in 1923 after working hard on this project.