I would just like to mention that in addition to Greek and Dantean Hells having the levels, there is also Buddhist Hell, Naraka.
Now not all schools of Buddhism subscribe to the belief in the Hells, but some do; for them, you can get reincarnated as not only a person or animal, but also as a god or demigod (these lives are similar to what Westerners call "Heaven"), as a "hungry ghost" (a sort of vampire-ghost hybrid that hangs out on Earth, haunting people), or as a "hell being." These are the worst sinners of all, and can wind up in any of sixteen levels of Hell, eight hot, eight cold. The cold ones are simply progressively colder, so not a lot of fascinating stuff there, but the hot Hells are fascinating. The top one is a massive plain of battle strewn with weapons, where everyone fights all day until everyone's dead; then they all come back to life and start over. (Oddly, this is also Emmanuel Swedenborg's vision of Hell, and pretty much the Norse idea of Heaven, Valhalla.) Next level down adds NPC's--I mean, demons--that hack everybody with flaming axes and saws (chainsaws, I hope). Third level replaces the demons with giant moving rocks that crush people. After this, it mostly turns into just increased heat, which apparently distracts everyone from the fighting; some levels involve stabbing with flaming spears, but hey, you're already on fire. The last level is described as what it would be like to be immortal and thrown into the Sun, still living but completely burned.
And then, as if that wasn't enough, there are sort of inter-level minor Hells for people too bad for one and not bad enough for the next; all four are pretty green meadows that you step into after finally leaving Hell. A past loved one appears to you, offering a refreshing drink of clean water, or whatever else might be most comforting. However...in Grater Hell, they appear at the top of a big grassy hill that turns into graters as you try to climb it. In Needle Hell, they're on the opposite side of a wide meadow, and all the blades of grass are needles. In Corpse Mud Hell, they offer you a dip in a nice pool, which turns into mud filled with corpses when you jump in. I feel like there's a fourth one...it's been a while since I read about the minor Hells.
Anyway, there's some more reference material for you. Enjoy!