 Over 100 years before the beginning of the story , giant humanoid creatures called Titans ( 巨人 , Kyojin ) suddenly appeared and nearly wiped out humanity , devouring them without remorse or reason . What remains of humanity now resides within three enormous concentric 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 of the Shiganshina district , a town at Wall Maria , allowing the smaller Titans to invade the district . An Armored Titan smashes clean through Wall Maria , forcing mankind 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 . 
