5. Kansai International Airport, Japan. The size of the artificial island of Kansai is 4 km in length and 2.5 km in width – they say, it is even visible from space. From an engineering point of view, the local airport is one of the most impressive in the world, but, unfortunately, frequent earthquakes, powerful cyclones and unstable seabed make this masterpiece of engineering one of the most dangerous airports in the world.