The first civilizations didn’t have satellites in the sky, mapping every inch of the world in real time. They only knew the parts of the world they’d seen. Everything beyond that, they had to imagine.
It made the world a stranger, more magical place. They saw their own homes at the center of a disc-like planet, surrounded by a threshold that would them into a world of magic that lay on the edges of the earth.
There are a handful of ancient world maps and encyclopedias that let us know how they saw that world. The Babylonians, the Greeks, and the Romans all left behind their own visions of our world and its furthest thresholds, each one giving a glimpse into how they saw the world and imagined the farthest reaches of the earth.