root-book

...East-Blue, West-Blue, South-Blue, and North-Blue are the four seas that constitute most of the whole planet. Humanity is thriving on the small patches of land which poke out of the four seas. These four seas are separated horizontally by a humongous mountain which encircles the whole planet, called Red Line, and vertically by, the most dangerous sea known to man, Grand-Line. Both sides of Grand-Line are flanked by strips of the windless sea called Calm Belt. The eternally windless strips of sea are impossible to cross with only wind-powered ships. It might be calm over the water, but the water hides nasty beings called sea kings, not to be disturbed as the name suggests.