Every year in the Church of the Holy Sepulchre in Jerusalem - where Christ was crucified, entombed and then believed by Christians to have risen from the dead - a holy fire is said to erupt spontaneously, lighting candles which eventually spread a flame that is carried around the world.
--Apeirogon, Colum McCann
This is another story that I have heard before, somewhere in the dim and distant past. Once a year, on the day before Orthodox Easter, a priest enters the tomb alone to observe the miraculous igniting of the candles by a shaft of blue light that rises from the stone slab whereupon the Lord had lain, and then to carry one candle out, bearing the holy flame, so that it might be shared to countless other candles. In olden times, the flame was transported throughout Jerusalem. In modern times, it is transferred all over the world, preserved in special vacuum globes. Before entering the tomb, the priest is thoroughly searched to make sure that he is not carrying any fire starting devices. Nonetheless, as with the mystery of the holy Shroud of Turin, this story is doubted by many and many have forwarded various explanations, which generally suggest dishonesty on the part of the monks who administer this ritual, as well as the priest of course. It is said, for instance, that the priest has a BIC lighter secreted in his beard, or that he is carrying some kind of flammable chemical, or that a flint or some such implement is hidden within the tomb itself, perhaps beneath the floor. Similarly, those who doubt the Shroud of Turin have "scientifically" proven it to be a fake, produced not at the time of Christ's death and resurrection, but in the Middle Ages. This was done by careful microscope examination of a bit of cloth from the shroud itself. The problem is, as it turned out, that the piece of cloth examined had been taken from a corner that had been damaged long ago in a fire. In the Middle Ages, curiously enough. What they examined was not the shroud, but a patch applied by nuns after the incident that had damaged it. Well, that's neither here nor there, the scientists say. The shroud is a fake. The holy fire is also a fake.
Who knows? I guess it is a matter of faith. It's a matter of what we believe.