Ruins of Azlant
In the ancient days long before the Age of Darkness, alien aboleths enhanced primitive humans, drawing them from their caves and nomadic lifestyle and setting them on the path to civilization and high culture as part of a curious experiment. For thousands of years these humans flourished, eventually forming humanity’s first great empire, Azlant, which stretched from coast to coast upon a vast island continent at the heart of the Arcadian Ocean. Azlant developed unparalleled art, philosophy, and science until its prideful leaders came to believe themselves superior to the aboleths who had raised them out of barbarism. In preemptive retaliation for their disloyalty, the aboleths looked to the stars, uniting in an unspeakable ritual that brought a shower of great stones tumbling from space. The resulting catastrophe shattered the island of Azlant, wiping out its people and creating a ruin-laden maze of crumbling sea canyons where once a mighty empire had stood.
-Inner Sea World Guide