The Ingalls Building in Cincinatti,Ohio. The first concrete skyscraper in the United States, it was designated a National Historic Civil Engineering Landmark in 1973.

The Ingalls Building in Cincinatti,Ohio. The first concrete skyscraper in the United States, it was designated a National Historic Civil Engineering Landmark in 1973.

The Ingalls Building in Cincinatti,Ohio. The first concrete skyscraper in the United States, it was designated a National Historic Civil Engineering Landmark in 1973.