Bridges are important structures, symbolically as well as physically.
They represent our right and ability of passage, characterize cities and time periods, and have always measured civilizations ability to build, use and defend them. Traveling, we may see bridges as a demarcation in our journey because they not only force us to leave the safety of the road we've come on, but require us to trust them to carry us over whatever lies below. Traveling far enough will always require bridges though, because they allow us to reach places we couldn't have reached on our own. Just as important, the act of crossing enables us to look at our surroundings temporarily free of our ties with the ground. Throughout our history, we have learned to accept our struggles and conflicts as a necessary and ongoing part of our existence.