I can only recommend this delightful and inspiring documentary. This is a true story, it's about the Cathedral that Justo Gallego Martinez built mainly on his own (he would accept some help and occasionally pay for day labourers) in his home town of Mejorada del Campo in Spain. He couldn't quite finish it, but what he achieved in 60 years working on it is impressive anyway.
Justo did this without any formal education as architect or even bricklayer, just powered by faith and 100% dedication. This incredible project is absolutely worth a film, and the film is well done. It gives us breathtaking views of Justo working on the cathedral, and shows some of his interesting attitude toward the materials (much of which is collected random stuff, and in general it was for free or as cheap as possible). Otherwise it shows what kind of person Justo is, how he interacts with others, and how they see him (we also get something to laugh). And then issues such as security, the legal status, and the future of the cathedral are explored. The security aspect alone is extremely fascinating; the guy reached age 96 apparently without any serious accidents. Looking at the stunts he did on a regular basis, this just beggars belief. He also seems to be quite competent regarding the security of the building for others, not from education, but from intuition, but the authorities of course have their issues with this. All of this is mostly explored through interviews with Justo himself and others more or less marginally involved (I was waiting for the question "What are your best tips for others who want to build their own cathedral" but this didn't happen - or Justo wouldn't respond).
Unfortunately the film could not follow Justo and the building chronologically through all 60 years; when people started to realise that this is worth a documentary, the project had already reached some maturity, and therefore we don't really see the cathedral grow, which is a pity, but this is of course not a complaint - it's just how it is and nothing else was possible.
Anyway, this will show you what one man with some proper determination and belief can do. And the cathedral is quite something.