The Sandglass of Time is a massive structure, containing within it the Sands of Time. Hidden underground for centuries, it was created by the Gods for the sole purpose of punishing humanity for their transgressions.
The Sandglass of Time is a massive structure grown out of the structure of caves beneath the city of Alamut. It contains the sandstorm the Gods created to destroy mankind within it. The Sandglass is located beneath the city of Alamut, guarded by Tamina's family. The only weapon with the ability to pierce its protective barrier is the Dagger of Time, which was given.
Events of The Sands of Time
When Nizam, the brother of Sharaman, obtained the Dagger of Time from Dastan and Tamina, he ventured deep underground to use the Sandglass of Time. Dastan and Tamina follow him down into the underground of Alamut to stop him, however, Nizam succeeds in piercing the sandglass with the Dagger.
Tamina attempted to stop him but is knocked over the edge and nearly falls to her death before Dastan catches her. Unable to save her and stop Nizam, Tamina makes the choice of sacrificing herself. After she falls to her death, Dastan turned his attention to Nizam and was able to prevent him from releasing the Sands of Time.