Pittsburgh is the "City of Bridges," and what remarkable bridges they are The area's challenging topography of deep ravines and mighty rivers--the Monongahela, Allegheny, and Ohio--set the stage for engineers, architects, and contractors to conquer the terrain with a variety of distinctive spans. Many were designed to be beautiful as well as functional. While other cities may have one signature bridge, Pittsburgh has such a wide variety that no single bridge can represent it. Pittsburgh's Bridges takes a comprehensive look at the design, construction, and, sometimes, demolition of the bridges that shaped Pittsburgh, ranging from the covered bridges of yesterday to those that define the skyline today.