The Legend of Korra
One of the story's settings is Republic City, a "metropolis powered by steam-type technology", "inhabited by people from all four nations". Here Korra must deal with rampant crime and an anti-bender revolt. Mike and Bryan have said that the world of Avatar has "definitely changed, and evolved, and advanced, but we're very conscious of keeping the same feeling. Not totally different, but it's definitely generations later."