There are places in this world that punch above their weight. People have a sense for them, and congregate there. As do other living things: salmon, bears, whales, herds of elk. Wolves.
These are places where something happens.
It might be a fall line where water breaks. Or a predictable fissure in the ice, formed by sub-ocean currents. Maybe a pass through the mountains.
A creek deep in the woods, surrounded by tall trees.
We find them. Collect there. We meet, and fight, and mate there. Connected by lines of force, which we follow like ancient game trails. Invisible, but inveterate.
The in-between places are deserts.
These are the oases.