City within the Mountain
Is a city inside a mountain like in some fantasy works feasible?
Houses in rocks and small cities in cliff faces exist in reality, perhaps most famously in the form of the incredible rock houses and underground cities of Cappadocia.
In Cappadocia, the rock is fairly soft, and wind erosion had done much of the work beforehand. Creating a city under a mountain in granite or other hard rock types would be a much harder task.
There is also City of Caves in Nottingham.
File:City of Caves Tannery.JPG
If it is feasible to excavate the structure, avoiding faults in the rock while doing so, and to ventilate and illuminate it, and it doesn’t get too hot or cold, and there is some viable way for the inhabitants to farm or trade for food in the surrounding lands, sure. After all, it’s just a city with a roof.
To some extent this idea was popularised by Tolkien, who in turn got the ideas from the dwarves/goblins of Norse mythology. In that context they were highly magical and not strictly speaking living creatures. It was simply their nature to live within rocks, half way into the land of the dead.
Tolkien’s dwarves are a lot more mundane. Their mansions in the Lonely Mountain, symbiotic with the City-Kingdom of Dale outside, could probably be reconstructed in a realistic way. The kingdom of Moria most likely couldn’t: it is unbelievably big, stretching across a mountain chain surrounded by mostly barren lands.
C S Lewis has an underground country, “Underland”, populated by glum “Earthmen” who turn out to actually be exiles from another realm, Bism, much deeper into the ground. So, in their case they hadn’t been digging deep, but been abducted to a place terrifyingly close to the surface.
