It isn't a terrible movie but it has some intrusive artistic pretensions and it uses the church as a background to tell the history of the church when I would have preferred the church and its idiosyncrasies be the subject with the history as a background.
But one thing struck me as eliding reality.
partial transcript (clip starts at about 32:30 into the film) :
Daughter of Antonio Gaudi's assistant : He [Antonio Gaudi's assistant] went there every day until July 18, 1936. Then the chaos of the civil war arrived. All the churches in Barcelona were burnt. [including the incomplete Sagrada Familia]
Narrator : The construction work on Sagrada Familia was abandoned. The Civil War raged on until, in the beginning of 1939, Barcelona fell, followed by Madrid shortly after. General Franco subsequently ruled Spain with an iron hand. Speaking Catalan was prohibited. In the Monastery of Montserrat, where sermons were still held in Catalan, 21 monks were murdered.
This suggests that Spain fell to Generalissimo Franco (true), he ruled with an iron hand (true), speaking Catalan was prohibited (sort of true) and then the monks were murdered; perhaps because they held sermons in Catalan. The problem I have is that the monks were murdered not by Franco's Nationalists but by the Republican side (more specifically, I'd guess POUM or the CNT) and they were murdered before the end of the War.
Additionally, "All the churches in Barcelona were burnt." is, I think, incorrect. I could be wrong but I believe in was an anti-catholic pogrom and other churches were not targeted (as Barcelona was overwhelmingly Catholic then Protestant churches were less significant). Again, this was done not by Franco's Nationalists but by the Republican side in territory not controlled by Franco.
Anti-clerical violence started before the Spanish Civil War. On May 10, 1931 (5 years before the start of the Spanish Civil War and less than a month after King Alfonso XIII fled) Spain saw convents set alight in Madrid, Málaga, Seville, Cádiz and Alicante and 2 dozen churches attacked.
As an aside, I've been told that the ban on Catalan was done with typical Spanish efficiency. Schools were ordered to teach in Castilian Spanish and so they "officially" complied. The school inspector would call ahead and let them know when an inspection was coming and on that day the students would put away their Catalan books and get out their Castilian books and class would be in Castilian as required. After the inspector left the Castilian books would go back in the closet and they continued in Catalan while the inspector could file a report that he is doing a great job and everything is how it is supposed to be.