Skip to main content


Date Innovations City Country State Society
1869 Bollman Truss Bridge Savage USA MD ASCE
1890 Walnut Street Bridge Harrisburd USA PA ASCE

We hope you enjoyed this essay.

Please support this 70-year tradition of trusted historical writing and the volunteers that sustain it with a donation to American Heritage.


Stay informed - subscribe to our newsletter.
The subscriber's email address.