Red Line

The Red Line (赤い土の大陸, Reddo Rain, literally translated as Continent of Red Earth) is a long continent that stretches across the entire world, from North to South, along the equivalent of Earth's Prime Meridian.

While the continent appears impassable for any boat wishing to cross between the seas or to certain sections of the Grand Line, there are certain pass points which a ship can cross between the Blues: up and down the waterways across Reverse Mountain (typically used to enter the Grand Line by pirates), by gaining government permission from the holy government land of Mariejois or by submerging into Fishman Island, which is placed around a hole that links directly between the first half of the Grand Line and the New World.

The Red Line is said to be 10,000 meters high from ocean level to either Mariejois or Fishman Island, meaning it is a total of 20,000 meters high, and is indestructible, meaning that no one can pass over it without using either of the entrances. Fisher Tiger, however, was said to have climbed the entire wall of the Red Line with his bare hands to attack Mariejois.