No. Ba Sing Se was considered to be the strongest fortress of all four nations, as it remained unconquered for centuries prior to the war. Even at the time of the infamous warlord Chin the Conqueror, Ba Sing Se was the only territory besides the Kyoshi Peninsula to remain free in the Earth Kingdom. Apparently, Chin would rather face the Avatar herself than try his luck at the Great Wall of Ba Sing Se. During the War, however, the walls of Ba Sing Se were broken through in some instances, such as during General Iroh's 600 day siege, when he broke through the outer walls; Princess Azula's drill mission, where the drill partially broke through the outer wall; and finally during the Coup of Ba Sing Se, when Dai Li agents took down parts of the wall for Fire Nation access.