728 ton pendulum

 In my research of large pendulums for the 10,000 Year Clock I came across the beautifully designed tuned mass damper in the Taipei 101 tower.  Basically really tall buildings are themselves massive pendulums, as they are built to sway in the wind and earthquakes.  However very tall buildings in earthquake zones need something to dampen this motion.

These mass dampers do that, and are used widely including the ones in the new buildings here in San Francisco that use baffled water tanks.  However the one pictured above is the first one I have seen designed with a high degree of aesthetics in mind…  It was clearly designed impress people on the building tour.  Below is a small animated image of how it counteracts building sway, it pretty much does what you do with your own weight when you are standing on a stool changing that light bulb and it starts to sway.