Two victims are simultaneously tortured on the rack. Woodcut. https://www.rawpixel.com/image/13984426/two-victims-are-simultaneously-tortured-the-rack-woodcutFree Image from public domain licenseNew Idria, California. The mercury extraction plant of the New Idria Quicksilver Mining Company where mercury is obtained… https://www.rawpixel.com/image/12339007/image-plant-sky-smokeFree Image from public domain licenseAesthetic gold medal paper element with white border https://www.rawpixel.com/image/9324083/image-aesthetic-art-vintageView licenseSkimobile up Cranmore Mountain, North Conway, New Hampshire. Sourced from the Library of Congress. https://www.rawpixel.com/image/12321040/image-cloud-person-skyFree Image from public domain licenseCivil engineering: a railway bridge at Cologne. Lithograph by J. R. Jobbins after E. H. Horne. https://www.rawpixel.com/image/14021203/image-background-pattern-public-domainFree Image from public domain licenseArchitecture: two composite roof trusses. Engraving by E. Turrell, 1847. https://www.rawpixel.com/image/13972517/architecture-two-composite-roof-trusses-engraving-turrell-1847Free 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/12247316/photo-image-person-sky-public-domainFree Image from public domain licenseBridge at St. Louis over the Mississippi by Robert Benecke https://www.rawpixel.com/image/14275649/bridge-st-louis-over-the-mississippi-robert-beneckeFree Image from public domain license[Untitled photo, possibly related to: A worker employed at the car-loading end of a bridge at the Milwaukee Western Fuel… https://www.rawpixel.com/image/12337232/image-public-domain-arch-architectureFree Image from public domain licenseA Cloth Wrapper and Koto Bridges (c. 1800 - c. 1805) by anonymous https://www.rawpixel.com/image/13769904/cloth-wrapper-and-koto-bridges-c-1800-1805-anonymousFree Image from public domain licenseWashington, 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 license[Untitled photo, possibly related to: New York, New York. Stairway from concourse to trains at the Pennsylvania railroad… https://www.rawpixel.com/image/12336998/image-people-public-domain-houseFree Image from public domain licenseMexico. Metlac Viaduct, Mexican Railroad. by Abel Briquet https://www.rawpixel.com/image/14323192/mexico-metlac-viaduct-mexican-railroad-abel-briquetFree Image from public domain license[Untitled photo, possibly related to: Old bridge, Scott's Run, West Virginia]. Sourced from the Library of Congress. https://www.rawpixel.com/image/12242825/photo-image-plant-tree-public-domainFree Image from public domain licenseA pipe aqueduct (the Wissahickon aqueduct), Philadelphia, Pennsylvania. Photograph, ca. 1880. https://www.rawpixel.com/image/14007356/photo-image-cloud-plant-personFree Image from public domain licenseOakland Bridge, San Francisco, Verenigde Staten: constructie (1936) by Wouter Cool https://www.rawpixel.com/image/13756408/photo-image-paper-sky-public-domainFree Image from public domain licensePart of Mays Avenue camp under the bridge. Oklahoma City, Oklahoma. See caption no. 21 by Russell Lee https://www.rawpixel.com/image/12143965/image-person-art-skyFree Image from public domain licenseMachinery: a pile-driving hammer, mounted on existing piles, with two men operating it. Engraving after J. Besson. https://www.rawpixel.com/image/13998604/image-paper-cartoon-personFree Image from public domain licenseMenufia Canal, Egypt: reconstruction work to the first Aswan Dam: men at work lowering a metal lock gate into the dam.… https://www.rawpixel.com/image/13971962/photo-image-person-sky-waterFree Image from public domain licenseDe Nieuwe Teertuinen te Amsterdam (1870 - 1926) by Willem Wenckebach https://www.rawpixel.com/image/13788737/nieuwe-teertuinen-amsterdam-1870-1926-willem-wenckebachFree 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 license[Untitled photo, possibly related to: Point Pleasant (vicinity), West Virginia. Bridges over the Kanawha River]. Sourced… https://www.rawpixel.com/image/12294424/photo-image-sky-tree-public-domainFree Image from public domain licenseAmerican Legion carnival near Bellows Falls, Vermont. Sourced from the Library of Congress. https://www.rawpixel.com/image/12278495/photo-image-person-sky-technologyFree Image from public domain 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 licenseGreat Northern ore docks at Allouez, Wisconsin. These are the largest and most modern in the world. Sourced from the Library… https://www.rawpixel.com/image/12284906/photo-image-sky-public-domain-natureFree Image from public domain licenseShenandoah, Pennsylvania. Second shaft tower at Maple Hill mine, as seen from first tower. Sourced from the Library of… https://www.rawpixel.com/image/12275785/photo-image-person-sky-mountainFree Image from public domain licenseShot from under a bridge https://www.rawpixel.com/image/534698/free-photo-image-gates-architecture-beamsView license[Untitled photo, possibly related to: Phelps Dodge refining company, El Paso, Texas. Copper is recovered from smoke that… https://www.rawpixel.com/image/12295410/photo-image-plant-sky-smokeFree Image from public domain license[Untitled photo, possibly related to: Children playing under the elevated on the southside of Chicago, Illinois] by Russell… https://www.rawpixel.com/image/12175641/image-person-art-vintageFree Image from public domain license[Untitled photo, possibly related to: Cleveland, Ohio. Unloading iron ore from a lake freighter by means of Hewlett [i.e.… https://www.rawpixel.com/image/12294145/photo-image-person-sky-public-domainFree Image from public domain licenseCleveland, Ohio. Unloading iron ore from a lake freighter by means of Hewlett [i.e., Hulett] unloaders at the Pennsylvania… https://www.rawpixel.com/image/12294151/photo-image-person-public-domain-factoryFree Image from public domain license[Untitled photo, possibly related to: Bingham Copper Mine, Utah. Main assembly yards, office, shops, air compressor and… https://www.rawpixel.com/image/12297481/photo-image-sky-public-domain-officeFree Image from public domain licenseTopock (vicinity), Arizona. A state line marker on a bridge over the Colorado River on the Atchison, Topeka and Santa Fe… https://www.rawpixel.com/image/12293824/photo-image-person-sky-public-domainFree Image from public domain licenseStreator, Illinois. The coal chutes along the Atchison, Topeka and Santa Fe Railroad between Chicago and Chillicothe… https://www.rawpixel.com/image/12289817/photo-image-sky-public-domain-archFree Image from public domain licenseLemont, Illinois. Crossing the drainage canal along the Atchison, Topeka, and Santa Fe Railroad between Chicago, and… https://www.rawpixel.com/image/12290134/photo-image-public-domain-arch-waterFree Image from public domain license[Untitled photo, possibly related to: Construction of new bridge, Tygart Valley Homesteads, West Virginia]. Sourced from the… https://www.rawpixel.com/image/12248155/photo-image-person-sky-airplaneFree Image from public domain licenseFort Loudon [i.e., Loudoun] Dam, Tennessee. Tennessee Valley Authority (TVA). Construction at night. Sourced from the… https://www.rawpixel.com/image/12340381/image-person-water-architectureFree Image from public domain licenseTopock (vicinity), Arizona. Military guard stationed at a bridge over the Colorado River along the Atchison, Topeka and… https://www.rawpixel.com/image/12293787/photo-image-person-sky-public-domainFree Image from public domain license[Untitled photo, possibly related to: Middletown, Connecticut, with a bridge across the Connecticut River]. Sourced from the… https://www.rawpixel.com/image/12279094/photo-image-sky-public-domain-archFree 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 licensePart of coal mine tipple with workers' homes in background. Pursglove Cleaning Plant No. 2, West Virginia. Sourced from the… https://www.rawpixel.com/image/12249066/photo-image-background-plant-personFree Image from public domain licenseIron ore dock. Grain elevator and coal loading docks in background. Allouez, Wisconsin. Sourced from the Library of Congress. https://www.rawpixel.com/image/12286174/photo-image-background-cloud-skyFree Image from public domain 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 licenseCleveland, Ohio. Unloading iron ore from a lake freighter by means of Hewlett [i.e., Hulett] unloaders at the Pennsylvania… https://www.rawpixel.com/image/12293890/photo-image-person-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/12290901/photo-image-technology-crosses-public-domainFree Image from public domain licenseBingham Copper Mine, Utah. Main assembly yards, office, shops, air compressor and waste material dumps up above as seen… https://www.rawpixel.com/image/12297479/photo-image-person-sky-public-domainFree Image from public domain licenseBarbed wire-surrounded barracks for Florida migrants working at Webster Canning Company, Cheriton, Virginia. Sourced from… https://www.rawpixel.com/image/12264699/photo-image-plant-grass-skyFree Image from public domain licenseChildren playing under the elevated on the southside of Chicago, Illinois by Russell Lee https://www.rawpixel.com/image/12175671/image-person-art-vintageFree Image from public domain licenseGallipolis, Ohio. Roller dam showing how river barrier is raised or lowered. Sourced from the Library of Congress. https://www.rawpixel.com/image/12294725/photo-image-public-domain-arch-waterFree 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 license[Untitled photo, possibly related to: San Sebastian, Puerto Rico (vicinity). Workman repairing a crane at a "central"].… https://www.rawpixel.com/image/12280591/photo-image-cloud-person-skyFree Image from public domain licenseMorenci, Arizona. Conveyor gallery where the copper is taken to the smelter, as shown in the background. Sourced from the… https://www.rawpixel.com/image/12294407/photo-image-background-public-domain-waterFree Image from public domain license[Untitled photo, possibly related to: New Idria, California. Tanks at the mercury extraction plant of the Quicksilver Mining… https://www.rawpixel.com/image/12297389/photo-image-plant-sky-technologyFree Image from public domain license[Untitled photo, possibly related to: Loading dock of flour mill. Port of Houston, Texas] by Russell Lee https://www.rawpixel.com/image/12174702/image-art-sky-vintageFree Image from public domain licensePoint Pleasant (vicinity), West Virginia. Bridges over the Kanawha River. Sourced from the Library of Congress. https://www.rawpixel.com/image/12293639/photo-image-plant-sky-treeFree Image from public domain licenseRailroad trestle. Ontonagon County, Michigan. Sourced from the Library of Congress. https://www.rawpixel.com/image/12286510/photo-image-plant-sky-public-domainFree Image from public domain licenseOre punchers going to work on docks. Allouez, Wisconsin. Sourced from the Library of Congress. https://www.rawpixel.com/image/12286129/photo-image-person-sky-public-domainFree Image from public domain licenseRow houses. Philadelphia, Pennsylvania. Sourced from the Library of Congress. https://www.rawpixel.com/image/12285248/photo-image-sky-road-public-domainFree Image from public domain licenseOne of the largest sawmills in the world. Employs many of the Resettlement Administration homesteaders at Longview.… https://www.rawpixel.com/image/12267322/photo-image-sky-public-domain-factoryFree Image from public domain license[Untitled photo, possibly related to: Coal mine tipple, Caples, West Virginia]. Sourced from the Library of Congress. https://www.rawpixel.com/image/12248189/photo-image-tree-road-mountainFree Image from public domain license[Untitled photo, possibly related to: Rock crusher at quarry. Tygart Valley, West Virginia]. Sourced from the Library of… https://www.rawpixel.com/image/12247893/photo-image-plant-sky-treeFree Image from public domain licenseTopock (vicinity), Arizona. Military guard stationed at a bridge over the Colorado River along the Atchison, Topeka and… https://www.rawpixel.com/image/12292698/photo-image-person-sky-public-domainFree Image from public domain license[Untitled photo, possibly related to: Cleveland, Ohio. Unloading iron ore from a lake freighter by means of Hewlett [i.e.… https://www.rawpixel.com/image/12293838/photo-image-person-sky-public-domainFree Image from public domain licenseSibley, Missouri. Crossing the Missouri River along the route of the Atchison, Topeka, and Santa Fe Railroad between… https://www.rawpixel.com/image/12291468/photo-image-sky-public-domain-archFree Image from public domain license