Short guide to the different major walls of the city of walls and secrets.

There are??at least five walls (not counting small walls seperating places in same area):
Two that surround the whole city:

1. Main wall: protecting it from attacks and seperating it from the plain or desert that the entire city of Ba Sing Se is in the middle of.
2. Inner wall: seperating wilderness and main gates from residential and financial area.

Three??seperating different social classes:

1. Lower-class wall: between middle and lower classes districts preventing homeless, refugees, etc. from getting to middle class area
2. Middle-class wall: between middle and upper classes districts preventing scholars, businessmen, etc. from getting to upper class area.
3. Upper-class wall: between upper-class district and royal palace, seperating politicians, non-active officers, and other non-royal officials from the royal castle.