A moratorium is in effect on adding information from Fire and Blood until December 20th.
The Wailing Tower is one of the towers of Harrenhal. It receives its name from the wailing noise that emanates from it when the wind blows from the north. These cracks formed when the stones fissured due to the intense heat of dragonbreath in the burning of Harrenhal during Aegon's Conquest. The common held belief among the inhabitants of the castle is that it is the cries of the long dead Harren the Black and his sons, though they died in Kingspyre Tower.
Beneath the Wailing Tower are cavernous vaults. The ground floor of the tower is storerooms and granaries. The upper stories has not been occupied for eighty years.