Stombarad is without question the most heavily fortified location on the continent, and perhaps the world. The fortifications are the closest its architects could get to impenetrable, it is almost entirely self-sufficient, and the legendary stubbornness of the dwarves will not see them ever break or falter. All that being said, we could certainly take it. Eventually. I estimate our casualty counts would start at five entire legions, with no upper limit.
The capital of Khazarak, Stombarad ('Cradled by the Mountain') is the most heavily fortified city in Nalunara, and perhaps the world. A nigh-impregnable fortress built on and in the mountain Rerdak, Stombarad is protected by the most formidable fortifications dwarven architects can create and entirely surrounded by a magically-maintained moat of lava. The Nazak Council has its seat here, and it is the hub of Khazarak's industry and commerce.
The most striking feature of the city is its lava moat. The moat takes the form of a natural-looking chasm that circles the entire city. It is around fifty metres from the lava to the surface, and the chasm's width varies between twenty and thirty-five metres. Five great bridges span the chasm, each of them overlooked by bastions bristling with weaponry. The bridges can be destroyed remotely should the need arise. As each bridge reaches the mountain it transitions into a huge tunnel sealed with great gates and lined with murderholes. Other than the five bridges, and the great gates that guard them, there is no access into Stombarad save magic or flight.
Most of the city is built into the mountain itself, but some dwarves prefer to live with access to the open air. By law there can be no access to the outside within a certain height of the lava moat, but above that is fair game. The middle third of the mountain's height is the most popular for outdoor structures, being high enough to comply with the law but avoiding the worst of the weather at the peak. In this region numerous homes and other structures dot the mountainside, along with gardens, parks and paths. Entrances into the mountain itself are tightly controlled and heavily guarded, even this high up.