Civilizations and the quest of nirvana

The idea of heaven and hell is pretty much embedded in outlook of social life and has been accepted since time immemorial. I have summarized them civilization wise as below:

Mesopotamian / Sumer civilization (4500 BC):

Mesopotamians believed in netherworld which is equivalent to hell. It was a dark place with no return. However, there were no punishments or torture. It was supposed to be just a place that is dull and mundane. There was no concept of heaven as well. Everyone who dies and have proper burial / funeral will be transported to netherworld. There will be 7 gates to the netherworld and the dead will transition after judgement from court of the Annunaki.