Ba Sing Se is a fictional city featured in the Nickelodeon shows "Avatar: the Last Airbender" and "Legend of Korra." It is the capital of the Earth Kingdom and is known for its great size and impenetrable walls.
Ba Sing Se is famous within the setting of the television show for withstanding a 600-day siege by the Fire Nation. It falls to a later Fire Nation siege during the second season of "Avatar: the Last Airbender." The Fire Nation army attempts to use a massive mechanical drill to breach the city walls, but fails; they later succeed by infiltrating the city disguised as Earth Kingdom warriors.