The Wailing Tower is one of the five melted towers of Harrenhal.
The ground floor of the tower contains storerooms and granaries, and the next two floors can house part of the garrison. The upper stories have not been occupied for eighty years, however, and the topmost story has huge bats. Beneath the Wailing Tower are cavernous vaults. Wind blowing from the north through cracks in the stone creates a wailing sound.
The tower's original name is unknown, and it received its current name from the wailing noise. The cracks formed when the stones fissured due to the intense heat of dragonfire in the burning of Harrenhal during Aegon's Conquest. The common belief among the inhabitants of the castle is that it is the cries of King Harren the Black and his sons, though they died in Kingspyre Tower.
A Clash of Kings
Lord Tywin Lannister orders that the upper stories of the Wailing Tower be made usable again. Arya Stark, serving incognito as "Weasel", sleeps on a bed of straw in the vaults beneath the Wailing Tower. Some of the Mountain's men sleep in the second floor of the tower.
Weese, the understeward of the Wailing Tower, is killed by his spotted dog near the tower. After the departure of Lord Tywin Lannister from Harrenhal, the new castellan, Ser Amory Lorch, has the Wailing Tower closed off, and the servants move to the cellars beneath Kingspyre Tower.
The topmost story was infested with nests of the huge black bats that House Whent had used for its sigil, and there were rats in the cellars as well ... and ghosts, some said, the spirits of Harren the Black and his sons.—thoughts of Arya Stark
A swirling wind gusted, drawing a high shivery scream from the cracks in the Wailing Tower.—thoughts of Arya Stark