The Tapestry of Time allows the Olympian gods to look into any person's past or present. It circles above the Abyss of Tartarus at Mt. Olympus. Zeus often looked at the tapestry of time – it was one of the ways that he kept an eye on former lovers such as Alcmene and favored children such as Hercules.
Zeus showed Hercules the Tapestry when he joined his father on Olympus. When Hercules besieged Olympus and instigated his final showdown with Hera, the combatants eventually wound up in the Tapestry room. Hera intended to hurl Hercules down the Abyss, and gleefully told Kronos that he would have company soon, but Hercules turned the tables on her, sending her hurtling down instead.("Reunions")