Ever since the Doom, Valyria has remained an absolute dead zone for mankind.
Historical records note that the cataclysm struck without warning. On that day, every volcano in Valyria erupted simultaneously, spewing countless clouds of ash, smoke, and fire into the sky, incinerating even the mighty dragons and their riders soaring through the heavens.
The greatest of ancient empires was now reduced to shattered ruins, and few who ventured into the wasteland ever returned alive. Even the bravest and most seasoned sailors dared not sail back into the ruined islands of Valyria.
Chapter 101