“Babylon 5 is a space station in neutral space more or less central to all five of the different alliances, human or alien. To get to one or the other, you have to pass through this sector of space. Thus, Babylon 5 has been created as a sort of port-of-call for travellers, statesmen, emissaries, traders, refugees and other, less savory characters.
As for locations inside B-5…we’ve designed a number of very different looks and locations to give it a non-claustrophobic feel.
By virtue of being patterned physically after the work of such scientists as Gerard K. O’Neill, the absolute center of the elongated station (which revolves to provide gravity) is a sort of hollow-world look, with fields and hydroponic gardens along the 360-degree circular section (which is about a half-mile, or a mile across)…and as you get closer to the absolute center, where a transport tube cuts from one end of the station to the other, naturally you get less and less gravity until you can literally hang suspended. This area is known as the Garden.” (Babylon 5 Universe)