What's that city in Avatar called? Bah-singsay or somesuch? Think of the slide transportation system, and a transportation system with gears, pulleys, and carts. One for light loads [carts] or large heavy loads [carts], or mediumly heavy loads or small heavy loads [slides]

Except really steep, for the most part. A single 'road' that stretches around a mountain is the main and only way up through the city, disregarding the housing and their ladders and stairs. One could go straight up a mountain-city, or they could go all the way around it at least what would seem a hundred times. What better way to beat any attackers than to make the air so thin that they can barely catch a breath when they're breathing normally, then make them run around in circles endlessly, or make them run up stairs and ladders. Even a Vocator would be tired.