For centuries, the Linnorm Kings, as well as their neighbors in Irrisen, have obsessed over an ancient ruin called Ice Spire. Rising from the frozen plains between Algidheart and Trollheim, Ice Spire was once the lair of an ancient Linnorm named Vyalldehun. While the spire rises jaggedly to a mere 30–40 feet, frozen steps lead down into level after level of monster-infested dungeons and ice caves still redolent of its former draconic occupant. No one has ever delved far enough below Ice Spire to find its bottom, although explorers who lived to tell of their experience say the deeper halls and chambers take on a vastly different, alien appearance.
Sources: Pathfinder Chronicles Campaign Setting