i think it inaccurate to anthropomorphize "heaven" by making it out to resemble a city.
look at that video of the sun i posted back a page or two. now that is pure energy, massive, responsible for all energy and life in our solar system, and honestly i think that it is a massive spiritual orgy. i think when we die, if we are spiritually pure enough to join, we go to the sun and take part in the meshing of souls and become part of that giant mass of energy which supports all life and is intuitively "god" for our solasr system