Avatar: The Great Age of Peace
Ba Sing Se
Ba Sing Se, or the Impenetrable City is the capitol of the Earth Kingdom and is located to the north east of the continent. The city is massive and houses the largest number of people in the world. The city is comprised of numerous sections separated by massive walls that can be completely isolated by Earth Benders in times of war.
Ba Sing Se is also the home of the Dai Li and organisation of spies, and other intelligence that somehow managed to survive having betrayed the Earth King in the year 100 ASC they are still a mysterious and dangerous force in the Earth Kingdom