Do you know what the most significant source of damage is to a building during an earthquake? While most people might think of the magnitude and intensity scales as a way to measure a quake's destructiveness, there is actually another important factor: an earthquake's period of oscillation. For example, during earthquakes with a long period of oscillation, tall buildings are most susceptible to damage because of a phenomenon called resonance. Studies have now begun to analyze the kind of ground cities are built upon in an effort to predict the period of earthquakes before they happen. We report on this cutting edge research protect buildings against giant earthquakes.