Washington, D.C. Steel piles to be driven as supports for a bridge structure. Sourced from the Library of Congress. https://www.rawpixel.com/image/12323931/image-person-public-domain-architectureFree Image from public domain licenseLeamington Spa, Warwickshire: pump room and Vicarage/Priory bridge. Steel engraving, 1851. https://www.rawpixel.com/image/14009679/image-paper-plant-personFree Image from public domain licenseEmployees of American Bridge Company (United States Steel). Ambridge, Pennsylvania. Sourced from the Library of Congress. https://www.rawpixel.com/image/12335828/image-face-person-public-domainFree Image from public domain licenseWashington, D.C. Construction of a bridge and road near Independence Avenue and 14th and 16th Streets, S.W. Bridge pier… https://www.rawpixel.com/image/12323781/image-person-road-public-domainFree Image from public domain license[Untitled photo, possibly related to: Parkway and Skyway, New York City to Long Island]. Sourced from the Library of… https://www.rawpixel.com/image/12246315/photo-image-sky-road-public-domainFree Image from public domain licenseIndustrial building with connecting steel walkways https://www.rawpixel.com/image/534673/free-photo-image-factory-architectural-architectureView licenseIndustrial building with connecting steel walkways https://www.rawpixel.com/image/534672/free-photo-image-factory-industry-building-structureView licenseFreight train operations on the Chicago and Northwestern Railroad between Chicago and Clinton, Iowa. The train crosses a… https://www.rawpixel.com/image/12290900/photo-image-person-crosses-public-domainFree Image from public domain licenseCrucible steel company. Pittsburgh, Pennsylvania. Sourced from the Library of Congress. https://www.rawpixel.com/image/12287029/photo-image-cloud-sky-public-domainFree Image from public domain license[Untitled photo, possibly related to: Freight train operations on the Chicago and Northwestern Railroad between Chicago and… https://www.rawpixel.com/image/12291204/photo-image-sky-tree-crossesFree Image from public domain licenseExterior of a modern airport https://www.rawpixel.com/image/534700/free-photo-image-airport-architectural-architectureView license[Untitled photo, possibly related to: Phelps Dodge refining company, El Paso, Texas. Copper is recovered from smoke that… https://www.rawpixel.com/image/12296703/photo-image-plant-sky-smokeFree Image from public domain license[Untitled photo, possibly related to: Freight train operations on the Chicago and Northwestern Railroad between Chicago and… https://www.rawpixel.com/image/12290901/photo-image-technology-crosses-public-domainFree Image from public domain licenseIndustrial building with connecting steel walkways https://www.rawpixel.com/image/534671/free-photo-image-steel-architecture-metal-structures-factory-architecturalView licenseLas Vegas, Nevada. Some completed and also some unfinished buildings of the Basic Magnesium Incorporated plant. The building… https://www.rawpixel.com/image/12297653/photo-image-plant-sky-public-domainFree Image from public domain license