With 120 mph winds and 50 inches of rain, when Typhoon Soudelor made landfall in Taiwan on August 8, it was powerful enough to knock cars off the road and permanently bend mailboxes. How did all 1,671 feet of Taipei 101, a supertall skyscraper that currently clocks in at the fourth tallest in the world, keep upright?

Like many other supertall structures, Taipei 101 has a tuned mass damper, in essence a giant pendulum within the building’s core that keeps the building from swaying too much. Because the structure is located near a fault line and is particularly vulnerable to both high winds and earthquakes, Taipei 101’s mass damper is monolithic. The more than 727-ton sphere is 18 feet in diameter and cost $4 million to build.

During the recent super typhoon, the damper set a record for how much it moved (or rather, how much the building moved around it), swaying a full three feet from its center position. Check it out in the video above.

[h/t: Gizmodo]