The Floating City

F-717. A mysterious element found 8,000 meters underground. Its appearance completely destroyed the survival logic of human beings for thousands of years. Once upon a time, everything human was rooted in the soil. Countries, cities, homes, classes—all are built on that solid ground that you can step on. Until the discovery of F-717: any material mixed with this substance can be suspended. From then on, human civilization officially entered the three-dimensional era. The story begins with a football.