3. Eads Bridge
The Eads Bridge in St. Louis, completed in 1874, marked a breakthrough in American bridge engineering. As the first major bridge built primarily of steel, it showcased bold new construction techniques—including the pioneering use of cantilever structures and pneumatic caissons for deep-water foundations. This remarkable achievement not only opened vital rail and road connections across the Mississippi River but also set new standards for durability and innovation in bridge building.
