I once heard someone say that Bridges is the art of mathematics, which is a sentiment I fully agree with.  Some of the older arch or suspension bridges have a beauty that have endured the test of time while fitting in classically with their surroundings.  Then, there are the more modern marvels which have taken a new approach for fitting in their environs.  Take a look at the two most photographed bridges in downtown Nashville, the Shelby Street Bridge and the Gateway Bridge; They are next to each other, one is old and one is new and they serve different functions.  The Shelby Street Bridge is what a beautiful bridge looked like from over a century ago whereas the Gateway Bridge is one of today's finest.