|“It's something truer than all the forest, seas, and deserts of this world combined. If anything, the pony civilization established above the chambers is the true temple.” Whitemane stared off into the constellations, as if seeking a home amidst the millions of twinkling stars. “What lies beneath is older than recorded time, and just as sacred.”|
|- Austraeoh, "Conversation"|
The Machine World refers to a layer of highly sophisticated but inactive machinery buried deep beneath the world.
Rainbow Dash discovers an ivory-white door marked with the symbol "Austraeoh" deep in the mines of Windthrow. Later, she finds a similar (silver metal) door beneath the Minotaur encampment, enters it, and navigates the machine layer until she reaches the Windthrow door from the inside. Later, with the help of Gold Petals, she lures summoned Chaos beasts through it and seals them inside.
At the bottom of the chasm which once housed the Darkstinian obelisk, Rainbow finds another Austraeoh door. After entering it, she manipulates the right controls to restore the obelisk to the city.
Shell and the Ledomaritan authorities were using civilians from Blue Shelf to excavate an Austraeoh door found underground. Unlike previous doors, this one is described as "a blue sheet of pale metal". As part of Rainbow, Belle, and Pilate's escape, they enter the door and use the controls to terraform the landscape, allowing them an easy exit to the surface.
A portion of the machine world had been exposed on the edge of a battlefield in Xona, as a side effect of Ledomaritan bombing.
A portion of the Machine World was found to be exposed in the chambers beneath Durandana. Unlike other instances, there was no engineered door to enter it. Rather, the entrance has been torn open by what Pilate speculates to be a falling piece of Stratopolis. The chamber was used by the Durandanans to keep their sacred relics of the Valkyrie.
There was an Austraeoh door in the silver mountain next to Amulek. The surface of this one was gold.
Grand Choke Edit
The Machine Tower in the middle of the Grand Choke sea is directly related to the Machine World, but unusually, it is well above ground. No other machine temple has ever been a free-standing structure.
Nealend Atoll Edit
A submerged "airlock" of sorts beneath the Nealend Atoll opened the way into a subterranean chamber, which Rainbow, Sinrar, Nick, Theanim, and Flare entered by boat after restoring the Shard of Verlaxion. Rainbow opened the door she found, encountered another cosmic vision, made contact with another Ruby Flame, and activated the machinery which caused another Machine Tower to rise in the center of the atoll.