Over 100 years before the beginning of the story on an alternate world, giant humanoid creatures called Titans (巨人, Kyojin) suddenly appeared and nearly wiped out humanity, devouring them without remorse or reason and only targeting them; they completely ignore other wildlife. What remains of humanity now resides within three enormous curtain walls: the outermost is Wall Maria (ウォール・マリア, Wōru Maria); the middle wall is Wall Rose (ウォール・ローゼ, Wōru Rōze, sometimes pronounced like rosé) and the innermost is Wall Sheena (ウォール・シーナ, Wōru Shīna, alt. "Wall Sina"). Inside these walls, humanity has lived in uneasy peace for one hundred years, many people growing up without ever having seen a Titan. This all changes when one day, a giant 60-meter (200 ft)-tall Colossus Titan mysteriously appears after a strike of lightning and breaches the outer wall (which is 50 meters tall) of the Shiganshina district, a town at Wall Maria, allowing the smaller Titans to invade the district. An Armored Titan smashes clean through the gate in Wall Maria, forcing humankind to abandon the land between Wall Maria and Wall Rose, evacuating the remaining population into the inner districts. The sudden influx of population causes turmoil and famine.