When a 7.4-magnitude earthquake rocked Taiwan on Wednesday, people inside the island’s tallest skyscraper, Taipei 101, were protected by a large yellow pendulum at the building’s center that helped absorb the shock.

Known as a “tuned mass damper” the 730-ton steel sphere is suspended between several floors at the top of the building, where it can be viewed by the public. The observatory is a popular tourist attraction in the capital city.

The sphere moves back and forth during earthquakes or typhoons that regularly lash the island, absorbing the force of any “violent swinging,” according to the Taipei 101 website. The damper’s engineers say it can curtail the building’s movement by up to 40 percent, reducing the queasiness felt by its occupants.