[@Mercenary Lord]There is no lore on the outside since its not important. The way I'm seeing it is that there's been at least one or two generations who have grown up within the confines but given how culture develops its more likely that its been many, many generations. People don't think there's anything beyond the walmart since many have never even seen the actual walls of the building itself much less doors. Plus when your live is reduced to just survival, you tend not to think of where things come from but care about the fact that you can get your hands on it.

Even the Roof people don't know it; some might be able to say they have been to the edge of the roof, beyond the urban maze of machinery, generators, solar panels, AC units and other bits and boos on the roof, but they have only ever spoken of an "endless grey plain with white lines that stretches for miles". History within the walls its isn't well kept so there is no info on what the world was like beyond since most just think that all that has existed was the Wal (although some stories of the time before do exist but have been corrupted and twisted). The only real history that people concern themselves with is who where great leaders/warriors and who recently raided them.

Do you have a character idea though?