If you read the whole thing, it will be worth it. Bear with me.
0:13–0:22: What we see here is unmistakably a statue of Avatar Aang, he stands perhaps fifty feet tall in the bay outside of Republic City. He is holding a staff, which does not look to be his glider. His left foot is perched upon what is rumored to be a white lotus flower. On the coast, the city can be seen, and interestingly, the glimmering lights seem to stretch for miles. A sailboat is also visible, insinuating that not everything is mechanized in the city; some things still are run manually, or by nature.
0:28–0:32: What we see here is Korra sitting on what appears to be a rocky Island, perhaps the island of Aang's statue or Air Temple Island. To the left (which is partially obscured by Korra's body) Republic City's downtown is lit brightly, with the towering 'pagoda style skyscrapers'. In the middle left is the town hall that is seen later in the trailer. To the far left is smaller buildings; which I think may be a historical district containing the city's first established neighborhoods.
0:39–0:45: This shot is my favorite scene of the trailer. What we can see here is Korra riding into Republic City on Naga. She appears on the opposite side of the city, separated by a large body of water. The area Korra appears in is likely a suburb of the immediate city. I picked up the yuppie feel in the area, judging from the man briefly seen behind Korra and Naga. Then of course – we see the suspension bridge, a feat of engineering. The bridge looks to be two to four lanes, probably an expressway. As the highway enters the immediate city is seems to narrow, possibly descending to the normal street level. It pains me to say this; as a future city planner myself, I was hoping for an expressway meandering through the city, if only Sokka and The Mechanist would have put their minds to it. If you noticed the Metalbender cop seen later in the trailer, you may have picked up that he has a logo on his hat; a hard to explain white shape. On the huge zeppelins (blimps) flying overhead in the city, the same logo is seen on a larger scale, but this time, it is colored golden, meaning the blimps belong to Metalbender cops.
0:45–0:48: This short scene obviously showcases a park, with many citizens scattered throughout the land. The trees display colorful fall foliage. A prominent system of streams can be found in the park, with interestingly designed bridges crossing each one. I'm guessing that this park is located behind downtown, on the opposite side of the city from the bay and the coastine. I'd guess that this park lines the side of the city facing the mountains. Take a quick look into the downtown area, the skyscrapers system seems to be larger than ever, rapid, and I mean rapid, growth would have had to occur for the city to be developed this much. How's that a for a concrete jungle?
0:48–0:51: What we see here is probably city hall, or the palace of United Republic. What I'm astounded by here is the detail, from the buildings, to the crowds, to the street lamps that line the plaza area on either side. The skyscrapers seen here look like typical American skyscrapers seen in the 1910s-1920s, but enlarged greatly, in some cases tripled in size.
1:07–1:12: Here we see the Metalbender cop I mentioned, note the insignia adorned on his hat. The buildings here look to be from a much more recent era, such as the 1960s.
1:13–1:14: Consider pausing the video here. What you see is in fact a stop light on a city street corner. The stop light uses the red, yellow, and green lights used today. The building in the center seems to boast superior masonry (from a much later era). A streetlamp is also visible, and to my interest, powerlines are posted on the side of the road.
1:19–1:20 Pausing the video here would again be wise. If you can redirect your attention from Korra kicking that guy's butt, have a look at the buildings behind her. The area seems to be a little more colorful and spacious, perhaps the city's historic district that I pointed out earlier?