Dumb question: What exactly is this for? Edit: "Taipei 101 skyscraper is protected by a large pendulum or big tuned mass damper weighing nearly 800 tons, that

Dumb question: What exactly is this for? Edit: "Taipei 101 skyscraper is protected by a large pendulum or big tuned mass damper weighing nearly 800 tons, that moves to compensate for the movement of the building so as not to collapse."