When you die, your spirit can pass through earth and solid rock, but finds air to be solidly impenetrable. Because of this, the earth has the same surface, but spirits walk on the inside of it. The roots of trees are what grows into the land of the dead. Moles and worms fly there, but slowly. The dead can see and swim through water, but it piles up in places-- in the case of the oceans, the water is miles high and larger than a continent. It is always purple twilight in that world.
When you die, you are reincarnated. But your memories were stored in your brain and rot with it. Your attitudes and aptitudes, your wisdom and your sins, all remain in your body and decay quickly. You continue, but you begin a completely new story, taking absolutely nothing from the previous one.
When you die, you enter a tunnel of light. Most people proceed forward along that until until they reach the light. Some retreat backwards into deeper and deeper darkness. You, however, notice the air-vents at the base of the tunnel, and manage to bash off the bolts with a loose stone, and slip into the unspeakably ancient infrastructure of that place. You find yourself in the workings of the world, and what happens to you is perhaps strangest of all...
When you die, you see your entire life before you as a long quilt, hanging on the wall. You can return to any point in your life you choose, and begin again from there. This has happened to you many, many times, but you never remember it.
When you die, you go to heaven. For most people, that is enough. But you are unsatisfied, and leave for the border, which is a parched desert that extends away from heaven for a thousand light-years in each direction. Along with a few strangers, you painfully begin the process of digging irrigation canals and planting hardy seeds. It is tedious, difficult work, but there is no time limit. You dig your home out of the cracked earth. Sometimes, in the evenings, you sing.