The Fourteen Fires, also known as the Fourteen Flames, are a chain of large volcanoes located across the neck of the Valyrian Peninsula. Four centuries before the War of the Five Kings, the Fourteen Fires and many lesser peaks erupted in violent explosions of fire and lava, consuming and destroy the Valyrian Freehold in an event known to history as the Doom of Valyria.
The Fourteen Fires stretched across the neck of the peninsula, dividing the Valyrian heartlands to the south from the Lands of the Long Summer to the north. One of the famed Valyrian roads crossed the chain, indicating there was at least one usable pass linking the two regions.
The Fourteen Fires were used as lairs for the Valyrian dragons. They were also used as mines, with slaves toiling underneath the burning mountains looking for precious metals and riches. This was extremely dangerous work, since as well as natural dangers, creatures such as firewyrms were enountered under and inside the volcanoes. According to the Faceless Men, their founders worked the mines underneath the Fourteen Fires and yearned for the day when they could take vengeance against the Valyrians.
On the night of the Doom, the Fourteen Fires erupted with tremendous force. The resulting firestorms, earthquakes and tidal waves shattered the Valyrian Peninsula, allowing the sea to come rushing in along the main faultline (along the volcanic chain). This reduced the Valyrian heartland to the south to a series of islands. The sea around the islands - soon known as the Smoking Sea - became poisonous, giving off vapours that were fatal to breathe.
At least some of the Fourteen Fires survived the Doom. Travellers who sail close to the shore report that the night sky still glows red over Valyria, and ash and dark clouds still boil from the surviving volcanoes.