Invisible Cities; Argia

The Influence Map for the Passage Argia.

Argia

When I read the Passage and found out that it was a underground city I immediately thought of the caves that you see with houses and streets that people went to, too survive wars but as I read on it a clearer picture started to form and it took me into thinking of a city with no roads only Pathways and stairs and maybe the occasional canal or two.

The biggest influence would be the top image of the canyon or crevice with the pathways and houses which was taken from Doctor Who Utopia.
As you can only see one shot from the episode It's hard to depict from it, so I'm imagining Argia would be dull looking on the outside like Mayan ruins but on the inside it is all foggy and dusty from the canals and you can only see a few lamps lit across the city which shines on to the roof of the cave therefor making the ceiling stones and gems glow to recreate a night sky feel.

And the main Capitol would be surrounded by Roots and dirt form the huge trees towering above on the surface.
The Interior of the houses would be what you find in any ordinary cabin back in the Victorian times and maybe some contraptions from the Steam Punk Era Combining the two times together to give that sort of fantasy feel to it.