Castle In The Sky
According to legend, humans were fascinated with the sky; therefore they created increasingly sophisticated ways of lifting aircraft from the ground. This eventually led to flying cities and fortresses. Due to an unspecified catastrophe (Probably a major storm), most of the flying cities were either destroyed or crashed back to the ground, forcing the survivors to live on the ground as before. One city, Laputa, is said to remain in the sky, concealed within the swirling clouds of a violent thunderstorm. While most people consider it to be fictional, some believe the legend is true and have sought to find the ancient city. Large airships still remain in common use.