Does anyone know what book or series I am thinking of? Honestly, this may be a movie, a book, a short story, etc. I can't quite remember. I just remember someone describing a story in which space travelers (presumably humans) come across a civilization with human-like figures. The society is more advanced than their own, and the aliens that inhabit it have an ethereal quality about them. Every so often, the city shakes, but the inhabitants are hesitant to explain why.
It is later revealed that the travelers have stumbled upon the civilization of Heaven, and the inhabitants are Angels. They have chained God up in the middle of the city, as after creating life/the universe, he went insane because it was too much to handle. Every so often, he throws fits of rage in his insanity.
I have no concept of how the story ends. Honestly, at this point it has been so long that I am trying to figure out if I made this story up or if it in fact exists.