Monorail

The monorail was the brainchild of Earth King Yi Ming an ingenious, but impatient ruler who was tired of having to spend two full days traveling from one end of his city to the other. He tasked his royal engineers with finding a solution to his traveling woes: "I want a faster traveling way! Make it so."

The result is the best mass-transit system in the entire world. Nobody has public transportation that's faster, more efficient, or safer. And it's all powered by Earthbending!