Ever wonder how a graceful and slender bridge can support enormous loads over truly astonishing spans? Why domes and free-standing arches survive earthquakes that flatten the rest of a city? Physicist Mark Denny looks at the large structures around us--tall buildings, long bridges, and big dams--and explains how they were designed and built and why they sometimes collapse, topple, or burst. Denny uses clear, accessible language to explain the physics behind such iconic structures as the Parthenon, the Eiffel Tower, the Forth Rail Bridge in Edinburgh, and Hoover Dam. His friendly approach allows readers to appreciate the core principles that keep these engineering marvels upright without having to master complex mathematical equations. Employing history, humor, and simple physics to consider such topics as when to use screws or nails, what trusses are, why iron beams are often I-shaped, and why medieval cathedrals have buttresses, Denny succeeds once again in making physics fun.