The world has evolved incredibly fast in the last 100 years, so it's almost hard to imagine how some things have changed in that time. Some cities have been "under the knife" countless times in recent decades and have become unrecognizable from the past. The most beautiful example is Dubai, which was more than a desert a decade and a half ago, but today it is one of the most vibrant cities in the world, where machines hum 24 hours a day and where the cityscape changes practically every day. But Dubai is far from an isolated case.