Rock formation. Valley of Fire. Clark County, Nevada. Sourced from the Library of Congress. https://www.rawpixel.com/image/12275352/photo-image-person-fire-skyFree Image from public domain licenseRock crusher crushing rock to be placed on trails on Pere Marquette recreational project. Grafton, Illinois. Sourced from… https://www.rawpixel.com/image/12268663/photo-image-dog-plant-personFree 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/12248154/photo-image-plant-sky-treeFree 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 licenseAmerican troops of the 57th Fighter Group sightseeing among Roman ruins in Tunisia. Sourced from the Library of Congress. https://www.rawpixel.com/image/12295651/photo-image-person-public-domain-wallFree Image from public domain license