The Houston Astrodome | Craig & Katherine M. Doherty

Our nation's unique identity has been formed, in large part, by the monuments and landmarks we have erected. Structures such as the famous Gateway Arch in St. Louis or the Washington Monument in Washington, D.C., stand today as permanent reminders of the people and events that have built a strong America. Many of these structures made history even as they were created -- most integrated the latest in design and technology and required the skills of thousands of workers.