Toph's first appearance was technically in this episode through a vision, but her first appearance as a character to be added to the team wasn't until two episodes later.
While the Northern and Southern Water Tribe are based on the Inuit culture of the Artic, the foggy swamp tribe is based on the Cajun bayou culture of the Southern United States.
The story of Hue achieving enlightenment under the Banion Grove Tree is based on the way Buddha achieved enlightenment.
The sign on the mask cart reads "Happy Travelers Opera Trope."