The Iron Mountains Edit
The Iron Mountains (also called the dwarven mountains or Northern Mountains) are fierce, sharp, deadly peaks that jut up along the entire northern skyline, barring all travel. They're home to most flying creatures that would happily eat a traveler, including griffins, dragons, and bennu.
Great veins of minerals run through the mountains. They're heavily mined, but even the complete collective effort of all of the dwarves in Sihiri has barely made a dent in their depths.
It's said there are openings to a horrifying dark region underneath those mountains, and that exploring the mountains would surely be suicide.
The Mountains are generally impassable. Only a few races have been able to settle in them, namely the dwarves (who build underground) and winged creatures who perch on crags and peaks. A strong air current rips up over the top of the mountains, making it impossible to fly over them (even for dragons).
Khaz Skarrenruf Edit
"Skarrenruf" is the largest dwarvish settlement in Sihiri. The entrance is built so carefully into the mountain that visitors may not notice it at all, though the gates are made of solid polished copper and lined with powerful runes. From there a tunnel leads deep into the mountains. Eventually small halls begin leading off from the main tunnel, and then the tunnel feeds into a Great Hall which continues indefinitely under the earth.
Although the place was built by dwarves, every space is cavernously large. Roofs stretch miles upward; it may take hours to cross a single room. Most supporting pillars are formed entirely of copper, intricately cast. There is no source of light - travelers must bring their own. But the ground is relatively even, especially in the entrance tunnel where centuries of feet have worn a path, and the hall is spacious enough to avoid running into much.
In the Common tongue, "Khaz Skarrenruf" translates to "blue hall" or "hall of the sky." The cavern was built through an enormous vein of copper. Most of the ground and many walls are made entirely of that metal. Over time the copper has oxidised to a brilliant, iridescent blue-green which reflects colour everywhere in the presence of light, giving the illusion of being outdoors or underwater.
Parts of Skarrenruf are still actively being mined, though activity has slowed over the years. A series of cart-tracks let out from the base of the mountains in six places, miles apart, providing an easy source of ore for nearby caravanners. Skarrenruf's ore is considered comparable with Philisia's for purity and worth.
A colony of griffins has set up their lairs to the east, where the wind has hollowed natural dens into the peaks. The griffins do not like visitors. Even if they did, there's no easy way to access the Aerie - you must be able to fly.
Every year a crop of griffins is born high up in the Aerie. Inevitably a few fall out of their nests and tumble down the mountains. Griffins do not recover their "skyless" kits, believing them to be weak. Therefore occasionally griffins can be found in the Wilds, though most of the species lives high above and refuses to interact with the world.
For more information on griffin society within the Aerie, see "Griffins" under "Races."
Iron Mountain Pass Edit
The Pass is just a legend, probably. It's said there is a tunnel which cuts all the way through the Mountains. Since the Mountains are impossible to scale, such a Pass would be invaluable, especially if there were resources on the other side.
There is a tunnel which leads into the Mountains, but so far nobody has managed to navigate the whole thing. The locals call it the Iron Mountain Pass anyway. In the dark, cold, wet spaces below the earth, temperatures can reach well below freezing and floods can sweep through in an instant, changing the landscape beyond recognition. Vast caverns full of crystals, salts, and ice line the edges of the Pass.
Strange monsters live under the ground here. There must be an opening to the Underdark somewhere in this mess, because drow and their massive spidery pets sometimes wander up into the tunnels. The caves also house ice wyrms, frost trolls, and all other beasties which like the cold and dark. Few creatures have eyes down here but their other senses are razor sharp. Travelers stand little chance of making it through.