Hong Kong is a tiny scrap of land that's had quite a storied history. Because of its geographic location and economic importance both as a population and trade center, Hong Kong has been disputed and fought over for centuries. It's now back in the hands of the Chinese, after the British relinquished their ownership of it in 1997.
Hosting so many people on so little land requires ingenious solutions, and there's no denying that this is one, but at the same time it's an ugly way of housing human beings. The average number of people per square kilometer in Hong Kong is 6,500. That figure is somewhat inflated by the existence of Kowloon City. The brutalist construction is home to more than 33,000 people in what is effectively one massive city block. That's bad news when it comes to the potential of disease breaking out and spreading rapidly. It's also bad news when it comes to concentrated human pollution seeping out into the land and atmosphere.