This one is fairly simple, may have been posted before.
I've seen a few posts regarding ATLs where the Tunguska meteor hit St. Petersburg or London, and the resultant chaos. What if another slammed into the crowd at Fatima? The children had been praying to the Virgin, prayers that had convinced the faithful and unsettled the local clergy and even government. Whatever the three children had seen or heard, and they never would recant, what if this last gathering was answered by the ghastly coincidence of, not so much a dancing sun, but a real fireball falling out of the sky, right onto the crowd?
The press and authorities had been alerted, many would have been curious to see what, if anything, was going to happen. Would this be considered the Wrath of God? Remember, WW1 was going on at the time, and the children had already been noted for their prayers and prophecy.