Hong Kong is one of the most densely populated places in the world and the growth of population here has been at a very high level for years. Nevertheless, it is not due to the high birth rate but the constant influx of immigrants attracted by the prospects offered by this dynamic city. Overcrowding poses an acute problem for the local authorities and they try to solve it a variety of ways. Coastal areas are commonly backfilled in order to acquire additional acreage for development. In addition, residential buildings constructed in Hong Kong are very high, a 50-storey apartment building comes as no surprise. Nevertheless, an apartment situated on high floors is much more expensive than the one on lower floors.