Great Barrier

The Great Barrier was an incredibly huge underground dome of rock and solid Protodermis that housed Metru Nui and the entire Silver Sea. It was here that the Toa Metru defeated Teridax in the Silver Sea.

During the Great Cataclysm, The Toa Metru escaped Metru Nui with a few Matoran through a hole in the Great Barrier, re-entered through the barrier to get the rest, and exited again to take them to Mata Nui.

LoMN Great Barrier Passageway

One of the holes in the Barrier.

The "ceiling" of the dome had two "suns" were actually holes in Mata Nui's surface. These holes were actually the Great Spirit's eyes, though they allowed sunlight to pass through them. After the Great Cataclysm one hole was covered up, but later uncovered by the Bohrok. There were also several gates in the barrier that connected them to Metru Nui.

Metru Nui
Ta-Metru Great FurnaceProtodermis Reclamation YardProtodermis Reclamation FurnaceFire PitsVakama's Forge
Ga-Metru Great TempleVhisola's HomeProtodermis LabsGa-Metru SchoolsGa-Metru DocksProtodermis FallsMatoran Recharge CenterFountains of Wisdom
Le-Metru Moto HubTest TrackChute SystemThe NotchChute StationSector ThreeTower of Toa
Po-Metru Sculpture FieldsMountain in BalanceFields of ConstructionCanyon of Unending WhispersPrison of the Dark HuntersAssembler's Village
Onu-Metru ArchivesFikou WebPrison of the Dark Hunters
Ko-Metru Knowledge TowersTowers of Thought
Other Locations ColiseumGreat BarrierSilver Sea