Hiller rotorcycle YROE-1 hovers in front of the Ames Hangar, June 11th, 1963. Original from NASA. Digitally enhanced by… https://www.rawpixel.com/image/441631/free-photo-image-helicopter-war-manFree Image from public domain licenseU.S. Army Master Sgt. Elizabeth Limon, with the 486th Civil Affairs Battalion, tries out a boy's bike near the site of a… https://www.rawpixel.com/image/8738737/photo-image-public-domain-doctors-childFree Image from public domain licenseOn October 1, 1891, Stanford University opened its doors after six years of planning and building. https://www.rawpixel.com/image/2110374/carol-highsmiths-californiaFree Image from public domain licenseOn October 1, 1891, Stanford University opened its doors after six years of planning and building. https://www.rawpixel.com/image/2110376/carol-highsmiths-californiaFree Image from public domain licensePalo Alto, United States. Original public domain image from Wikimedia Commons https://www.rawpixel.com/image/3291908/free-photo-image-asphalt-birch-busFree Image from public domain licenseClay Monument and Palo Alto Valley/View from Sharp Mountain, Schuylkill County/This view part of the town called the… https://www.rawpixel.com/image/14286049/photo-image-person-cross-artFree Image from public domain license