To protect a historic structure from natural hazards such as earthquakes and hurricanes, the building must be kept from moving in unanticipated ways under the conditions imposed by the hazard. The author briefly discusses the types of movements and forces produced by earthquakes and hurricanes. Then, for each type of movement--entire building moving upward, entire building moving horizontally, different layers moving laterally at different rates, walls moving at different rates, roofing and building moving separately, decorative elements and building moving separately, internal nonstructural elements (e.g., water pipes) and building moving separately--he describes and illustrates the stresses and damages and suggests structural preventive measures. -- AATA