A geofront is a science fiction concept, referring to a large, excavated subterranean space typically used for urban expansion.
The concept appears in numerous media:
Anime: Patlabor (ep 19), Neon Genesis Evangelion, Ghost in the Shell, CB Chara Nagai Go World, Pandora in the Crimson Shell: Ghost Urn;
Video games: Ace Combat 3: Electrosphere, The Legend of Heroes: Zero no Kiseki & Ao no Kiseki
In other franchises: Doctor Who, The Matrix;
Literature: Isaac Asimov's novel The Caves of Steel. A parent concept of a subterranean world is also found in Jules Verne's novel A Journey to the Center of the Earth.
