The most remarkable thing about 181 Fremont—San Francisco’s third-tallest tower, designed by Heller Manus Architects—is not the penthouse’s asking price ($42 million). Rather, it’s an innovative yet unglamorous structural detail: a viscous damper system that far exceeds California Code earthquake-performance objectives for buildings of 181 Fremont’s class, allowing immediate reoccupation after a seismic event.