Hardhome

A mystery.

Staying in Westeros, but far past the Wall, we have Hardhome.

This isn't just an episode of the Game of Thrones TV show, it was the closest the wildlings ever got to a proper city or large town.

But what we read in the World of Ice and Fire is this.

Hardhome had been halfway toward becoming a town, the only true town north of the Wall, until the night 600 years ago when Hell had swallowed it.

Its people had been carried off into slavery or slaughtered for meat, depending on which version of the tale you believed, their homes and halls consumed in a conflagration that burned so hot that watchers on the Wall far to the south had thought the sun was rising in the north.

Afterward, ashes rained down on haunted forest and shivering sea alike for almost half a year.

Traders reported finding only nightmarish devastation where Hardhome had stood, a landscape of charred trees and burned bones, waters choked with swollen corpses, blood-chilling shrieks echoing from the cave mouths that pocked the great cliff that loomed above the settlement.

As for the Drowned Spirits, they seem to be a reference to the dead marshes of J.R.R. Tolkien's lore, but they may have been mentioned in A Song of Ice and Fire before The World of Ice and Fire.

In Jon Snow's letter from Hardhome.

Attempt to take the Stormcrow defeated.

Six crew dead.