Holy Terra is the ancient homeworld of humanity and the sacred heart of the Imperium, revered across a million systems as the birthplace of the species and the seat of the Emperor of Mankind. Once simply Earth, the planet was transformed over millennia of war, industry, and worship into a single continent-spanning conurbation of cathedrals, fortresses, and manufactory sprawl, its ancient oceans long drained or entombed beneath rockcrete.
At its center rises the Imperial Palace, a mountain-sized complex of spires and ramparts that houses the Sanctum Imperialis and the throne room of the master of mankind. Countless pilgrims journey here to die within sight of the walls, and the planet's orbital defenses, void shields, and standing armies make it the most heavily fortified world in the galaxy.
Terra serves as the administrative nerve of the Imperium, home to the towering bureaucracies of the Adeptus Terra and the endless scriptoria that record the affairs of an interstellar dominion. It is also a place of profound decay, its surface choked by the weight of ten thousand years of accumulated faith and refuse. To the faithful it remains the holiest ground imaginable, a world where devotion and dust settle together in equal measure.