Is their such thing as "hollow mountains"? By this, I basically mean mountains with hollowed caverns within them, but not being entirely hollow. I've done some quick searches on google to no avail, but figured maybe someone on here could help me out. Thanks!
I'm not sure this is possible by natural means. Think of building a really small mountain out of wet sand. It wouldn't be naturally hollow unless you make it hollow. Even if you did succeed in making it hollow, it would eventually collapse. The only thing that might make it hollow is human activity. And I guess one could consider a volcano to be sort of hollow but I don't know if you want to use that.
There are certainly mountains with caves, but if you are thinking of mountains with enough hollow space to contain a dwarven city, then prohably not.
I don't mean anything big enough to contain, as Etan stated, a "dwarven city". Just a cave beneath a mountain,possibly caused by a river. Not too big, maybe 20-30 ft. tall at the most.
of course there are... not an actual mountain, but big enough for one, the most famous is the rock of gibraltar, which is honeycombed with caverns that are used by the military who guard that false symbol of 'solidity'... and in the us, the cheyenne mountain war room is 1,000 feet beneath the surface... there are other mountains in the us that have been somewhat 'hollowed out' for storage of nuclear waste and weapons and the infamous area 51 in nevada is said to include a minor mountain that contains classified stuff of some kind...
The CIA built vast complexes of caves and reinforced existing ones in Afghanistan during the 80ies. In Tora Bora for instance, there's enough place for 1000 people. The complex was used to hide caches of weapons (specially AT weapons and Stinger missiles). There are offices and bedrooms, lighting and ventilation. Power is generated from mountain streams.
It also provides the main area of focus for the science fiction program Stargate: SG1. When the initial, actual project was begun for the NORAD site, it was discovered that Cheyenne Mountain was nowhere near as structuraly sound as believed. A giant cement dome had to be constructed within the area which had been hollowed out in order to satisfy the requirement that the site be able to withstand a direct nuclear impact. It was subsequently proven that even with the measures taken, the site would never have withstood such an attack.
