His ambitious undertaking is labeled the “Cathedral of Faith” on internet maps, even though it has received no official backing from officials of the Catholic Church. Flanked by two cloisters and crowned by an unfinished 125-foot-tall cupola, it attracts tourists on the weekend, helping lift the local economy.

“This man has built something incredible against all odds and turned it into a symbol of our town,” said Victor Morillo, a resident who can see the cupola from the balcony of his apartment. “The Town Hall should have done a lot more to help and should certainly not allow anything bad to happen to this cathedral after he dies.”

Mr. Gallego, however, is unmoved by this kind of support, just as he has been unshaken by past criticism of his project and his own personality, sometimes derided as that of an exalted former monk. He is also unfazed that he has never received any public financing, even in a country that is mostly Catholic and whose infrastructure has been heavily subsidized.

“I’ve not been building this to get money or fame, just as I’m not here to listen to people decide whether I’m mad or unique,” he said. “I’m fully responsible for my work and I’m not looking for the authorities to have any say.”