Ninjago City does seem like a large city. I imagine it would be one of the largest in the world. It does get attacked consistantly by evil. The current largest city in the world is Tokyo, Japan at 37.4 million people. The largest city in the US is New York City at 18.8 million people. I imagine (definitely not just throwing around a random number) Ninjago City would have a population of 20.5 million people, making it the 6th largest city in the world. Ninjago as a whole would have 275 million people, making it the 4th largest nation in the world.
Also, if it would be this large and attacked all the time, you imagine that the police wouldn't be a joke and that the military (which we have never seen or don't even know if it exist) would be called.
