The Ruins of Thaurissan are what remains of the Dark Iron dwarves' original city of Thaurissan (aka city of Thaurisan). Little is known of the great city, and Royal Historian Archesonus has led research into the ruins found in the Burning Steppes, to reveal some information about the place. It was once the Dark Iron kingdom.
Hundreds of years ago, the city, named after Sorcerer-thane Thaurissan, stood proudly in a lush expanse of land that is now the dilapidated Burning Steppes.
Thaurissan was home to the nation of Dark Iron dwarves and at the time, in the midst of a civil war among the dwarven nation at large.
That area of the world was at one point in time part of the Redridge Mountains — until the day that Thaurissan was consumed by a gigantic explosion, as Thaurissan attempted to summon the ancient Firelord Ragnaros. The city lay in ruin, the surrounding areas reduced to an ashy wasteland.
The Dark Irons that survived made their way into the mountain and began rebuilding their city.
An expedition was commissioned, to find mysterious relics rumored to still lie within the ruins of the city. While none of the relics were able to be brought back in one piece, the information revealed was still priceless. Apparently, merely touching the relics caused memories of the destruction of Thaurissan to overwhelm the explorers, flooding his sight with visions of the terrible ruin wrought upon the city.
Notes taken by the explorers are recorded here:
- "...threatened, 'Defiler... you will be punished for this incursion.' A symbol of flame radiated from the relic before it crumbled to the earth."
- "I could hear tormented voices pleading... 'Help us, outsider.' even as the relic crumbled to dust in my hands... I saw eight Dark Iron dwarves performing some sort of ritual..."
- "...me to 'Leave this place.' A white hot arc of flame sprung from the relic, and I saw a lone Dark Iron dwarf, surrounded by seven corpses, kneeling before a monolith of flame."
- "...only make out 'Do not taint these ruins, mortal,' before I was engulfed in a blinding flash of light. A creature composes entirely of flame is the only thing I can remember seeing."
- "I heard the words 'You will perish here' as my mind was filled with visions of chaos and destruction."
- "...'He cannot be defeated,' that much I am sure of. The relic burned away to nothing in my hands. Whatever destroyed this city was a being not of this world."
some taken from 
In CataclysmThis section concerns content exclusive to Cataclysm.
It appears there may be a neutral quest hub in the SW section of the area that may also contain a flight master.