With almost 50 million people in Korea and a land mass that is smaller than some states in the USA... almost everyone lives in what Americans would consider apartments (or condos). I think it's normal in any big city. These buildings are everywhere in Korea and they're HUGE!!! Still, I look up and it's amazing to me... buildings as high as mountains. It really is an amazing sight.
On my way to Seoul I got a few pictures of some complexes under construction. Not just one... but an entire group of them - like they were building an entire neighborhood at once.
And when they finish... it looks something like this: