There are some important cities in the kingdom of Ferelden. Most are human cities and only two dwarven cities are known to the people. Long ago the Darkspawn conquered the Deep Roads and eliminated many dwarves and their cities crumbled. Also the elves are living as outsiders in the human cities these days. Only the Dalish Elves are living in small camps, far away from their ancient places, always trying to keep their ancient knowledge alive for their descendants.
Representing the furthest point of encroachment by the ancient Tevinter Imperium into the barbarian lands of the southeast, the fortress of Ostagar was once one of the most important defensive Imperial holdings south of the Waking Sea. It stood at the edge of the Korcari Wilds and watched for any signs of invasion by the barbarians today known as the Chasind wilders.
Straddling a narrow pass in the hills, the fortress needed to be by-passed in order for the Wilders to reach the fertile lowlands to the north and proved to be exceedingly difficult for the Wilders to attack due to its naturally defensible position. Like most Imperial holdings in the south, Ostagar was abandoned after Tevinter's collapse during the First Blight.
It was successfully sacked by the Chasind wilders and then, as the Chasind threat dwindled following the creation of the modern Ferelden nation, fell to ruin completely. It has remained unmanned for four centuries, though most of the walls still stand -- as does the tall Tower of Ishal, named after the great Archon that ordered its construction -- and Ostagar remains a testament to the magical power of the Imperium that created it.
The Lands of the dwarves once were numerous and extended far beyond the Frostback Mountains. The thaigs were once almost beyond counting. Kal-Sharok was the capital then, home to all noble houses of the dwarves, and Orzammar was simply home to the Miner and Smith castes.
It was with the coming of the Tevinter Imperium that things began to change. Paragon Garal moved the seat of power to Orzammar to more closely oversee the trade that began with the surface. It seemed that the dwarves were entering a new age of prosperity. They taught such concepts as commerce and coinage to the humans, and in return they provided them with a wealth of things the dwarves had never possessed in the deep: grains and wood.
The dwarven memories hold no explanations for the coming of the darkspawn, only questions. One moment there was no such thing as a darkspawn, and the next there was. The darkspawn poured into the Deep Roads like smoke, and the Warrior Caste struggled to hold them back. Countless thaigs were lost in that first Blight. But as ever, in the time of need, a Paragon arose. Paragon Aeducan led the defenses of Orzammar, and the dwarves were saved from utter annihilation.
The cost of victory, however, was great. The Deep Roads were sealed to hold back the darkspawn, cutting off thaigs and whole cities forever. Only Orzammar itself remained, the last bastion of an ancient empire that had once sprawled over all of the deep of Thedas. The dwarves had been brought low, but they had survived.
Several interesting places are designed by Bioware to keep your character busy. There are ruins in the Brecilian Forest as well as the Circle Tower in Lake Calenhad. The most interesting place seems to be the underground, the Deep Roads. Here you can read short descriptions of the best places.
Deep Roads are old underground roads made by the dwarves. Once there were runes and famous ornaments on the walls, steps went down deep into the earth, above are hundreds of feets of stone. These roads are hugh tunnels that lead to their thaigs and citys, some old rusted wagons and rails here and there telling from the mining activity of the dwarves.
The thaigs are impressing as well as the Giant Spiders, that have spun their webs therein now. A few hundred feets high the ceiling of the thaigs can only be imagined when standing at the ground which is covered with ornaments. Statues, showing the Paragons of the Dwarves, are build to last for eternity. They stand there mileshigh, as if to prevent the ceiling from dropping down.
Now with the Darkspawn filling those Deep Roads, the dwarves have only the "Legion of the Death" fighting against the spawn. Dwarves who are not worthy to live in Orzammar any longer, go down into the roads to fight the Darkspawn and get back their honor and their family names. They are painted with skulls on their faces and they are meant to never get back anywhere, only to die fighting the Darkspawn.
The Deep Roads were once sealed by the dwarves, sealed with big steel doors, and in some places those seals are so near to the surface, that it is possible to get in, but maybe never come out there. The city of Gwaren was build above an old Dwarven outpost and here is one of that seals leading into a Deep Road hundreds of feets under the stone.