I thought the massive water tank at the top of One Rincon Hill , to control swaying in the event of earthquakes, was interesting: https://www.sfgate.com/bayarea/article/One-Rincon-tower-feat...
> The damper system has no connection with the seismic safety of One Rincon. It is always a challenge to build a tall structure in earthquake country, and One Rincon's engineering response was to use outriggers, tall reinforced concrete columns built around the core of the building.