In "By the Waters of Babylon" what does John learn when he achieves his rite of passage?

John's realization when he finally reaches the "Place of the Gods" is that the so-called Gods were just human beings like himself and their once wonderful city, which we know as New York, was destroyed by some horrible weapon. He longs for the knowledge these men possessed and is sure that he can use that knowledge more wisely than they. He decides that, as a new priest, he will help his people make a new beginning, and he will help the recover the lost knowledge in order to build a new civilization.