The Walls were built more than acentury ago, when humanity was brought to the edge of extinction at the hand of the Titans. In response to this looming threat, the humans made huge Walls to protect their last stronghold. The Walls reach about 50 meters in height and reach four or five times a human's height below the ground.

The Walls are too long to beguarded in their entirety. The tops of the Walls are lined with cannons, which can fire on approaching Titans, even though they are not particularly effective due to the Titan's regeneration abilities. To account for this, each one has four towns on their periphery. As Titans are drawn towards large concentrations of people, humanity can focus its defenses at these towns and not the rest of the Wall. These towns are where the poorer citizens of humanity live, since they are at greater risk of a Titan invasion. The distance from Wall Maria toWall Rose is about 100 km, the distance from Wall Rose to Wall Sina is about 130 km, and the radius of Wall Sina is about 250 km. Assuming the walls to be perfect circles, this would make the total area inside the walls 723,823 km roughly twice the size of real world Germany.