It was completed in 1831, and is now on the List of historic civil engineering landmarks.
The 41-mile aqueduct was considered an engineering landmark when it was finished in 1842.
The wheel is the only rotating boat lift of its kind in the world, and is regarded as an engineering landmark for Scotland.
The bridge is the oldest surviving iron bridge in Alabama, making it an important transportation and engineering landmark for the state.
It was also designated an Historic Civil Engineering Landmark in 1992.
It was designated a Historic Mechanical Engineering Landmark in 1979.
In 1989 it was listed among the approximately 250 Historic Civil Engineering Landmarks.
The blowout preventer was designated as a Mechanical Engineering Landmark in 2003.
Instead of demolishing the structure, the Michigan Department of Transportation preserved it as an engineering landmark.
