In the Creation War (1486 DE - 8777 DE) , a primordial named Thyrm came to an area of Ice Cap that he named Netheram. In this area he set out to build a palace and a ring of fortifications. He thought that if the primordial invasion of Bal-Kriav failed, he would fall back to Netheram and hole up in Netheram. He created blueprints imbued with magic that were 10' wide and 20' long. Looking into certain areas would allow the viewer to drill down into other blueprints, so that one large blueprint would give access to a theoretically endless series of blueprints. In time, Thyrms Blueprints became tainted from chaotic energies or perhaps a flux in the Web of Magic and they took on a life of their own. When someone comes into possession of Thyrms Blueprints, they don't reveal what was done at Netheram, but other possibilities, grandiose construction efforts requiring the toil of thousands and sometimes centuries of effort.
The frost giants built fortifications and underground complexes across Netheram for seven hundred years. The toil of the enthralled ending only after the mystical blueprints were stolen by Azwyr Amoruk thieves.
There are other places that would make one think that their builders fell upon Thyrms Blueprints. The first is Krarthjar. This fire giant hold in Krarthjar is of such scale that it could never have been fully secured. The other is a maze beneath the Eastern Shar called the Apex Maze. The tunnels of this place cover no less than twenty square miles and are still being worked on today. Many of Nevicanad's, the architect of the maze, diaries have references to an "accursed blueprint".