Unidentified young girl in curls, standing, holding a hat, resting her other arm on a table with books on top by Joseph Brown https://www.rawpixel.com/image/14307783/image-face-person-booksFree Image from public domain licensePortrait of an Elderly Man in Hat Holding Some Tools by Oscar Gustave Rejlander https://www.rawpixel.com/image/14284144/portrait-elderly-man-hat-holding-some-tools-oscar-gustave-rejlanderFree Image from public domain licenseRobert John Thornton. Stipple engraving by W. Ridley, 1803, after J. Russell. https://www.rawpixel.com/image/14002758/robert-john-thornton-stipple-engraving-ridley-1803-after-russellFree Image from public domain licenseVictoria, Crown Princess of Germany, Princess Royal of Great Britain by Camille Silvy https://www.rawpixel.com/image/14312170/image-face-person-crownFree Image from public domain licenseAureolus Theophrastus Bombastus von Hohenheim [Paracelsus]. Line engraving by J. B. Fosseyeux. https://www.rawpixel.com/image/13988457/image-face-person-artFree Image from public domain licenseNicolaus Copernicus. Line engraving by M. Deyerl after a design attributed to M. Basaiti, 1512. https://www.rawpixel.com/image/13995947/image-paper-face-personFree Image from public domain licensePresident Barack Obama delivers remarks during a meeting with newly elected governors at Blair House in Washington, D.C.… https://www.rawpixel.com/image/4050600/photo-image-flower-art-plantFree Image from public domain licenseSculptured by erosion, 05/1972. Photographer: Norton, Boyd. Original public domain image from Flickr https://www.rawpixel.com/image/8770016/photo-image-vintage-woman-peopleFree Image from public domain licenseA man or deity. Watercolour attributed to a Chinese painter. https://www.rawpixel.com/image/13967894/man-deity-watercolour-attributed-chinese-painterFree Image from public domain licenseUnidentified couple, both seated, man with moustachless beard and woman with ringlets. by I F Alger https://www.rawpixel.com/image/14307038/image-face-person-artFree Image from public domain licenseFree dog's head between wooden fence in black and white public domain CC0 photo. https://www.rawpixel.com/image/5912573/image-background-face-public-domainFree Image from public domain licenseRené Descartes. Line engraving by J. Suyderhoeff after F. Hals, 1649. https://www.rawpixel.com/image/13983143/rene-descartes-line-engraving-suyderhoeff-after-hals-1649Free Image from public domain licenseUnidentified elderly woman, printed in quasi-oval style by Louis L Liberty https://www.rawpixel.com/image/14285418/unidentified-elderly-woman-printed-quasi-oval-style-louis-libertyFree Image from public domain licensePresident Barack Obama speaks at Cairo University in Cairo, Thursday, June 4, 2009. https://www.rawpixel.com/image/4051279/image-public-domain-person-photoFree Image from public domain licenseBurchard David Mauchart. Mezzotint by J. J. Haid after W. D. Maier. https://www.rawpixel.com/image/13995299/burchard-david-mauchart-mezzotint-haid-after-maierFree Image from public domain licenseAbraham Rees. Stipple engraving by J. Thomson, 1820, after J. Opie. https://www.rawpixel.com/image/13974685/abraham-rees-stipple-engraving-thomson-1820-after-opieFree Image from public domain licenseJohn Locke. Stipple engraving by H. Adlard, 1829, after Sir G. Kneller. https://www.rawpixel.com/image/14019361/john-locke-stipple-engraving-adlard-1829-after-sir-knellerFree Image from public domain licenseEvangelista Torricelli. Line engraving by Tomba after himself. https://www.rawpixel.com/image/14013460/evangelista-torricelli-line-engraving-tomba-after-himselfFree Image from public domain licenseJoannes Pistorius. Line engraving by D. Custos after himself. https://www.rawpixel.com/image/13986182/joannes-pistorius-line-engraving-custos-after-himselfFree Image from public domain licenseFresh waves near Cape of Good Hope. Original public domain image from Wikimedia Commons https://www.rawpixel.com/image/3288501/free-photo-image-sea-turtles-adventure-alpsFree Image from public domain licenseAntonio Cocchi. Line engraving by V. Rossi, 1758, after L. Frati. https://www.rawpixel.com/image/14017767/antonio-cocchi-line-engraving-rossi-1758-after-fratiFree Image from public domain licenseJohn Locke. Line engraving by P. Tanjé, 1754, after Sir G. Kneller, 1697. https://www.rawpixel.com/image/13988111/john-locke-line-engraving-tanje-1754-after-sir-kneller-1697Free Image from public domain licenseTwo skeletons flank a tree to which they attach a large cloth. Etching by Stefano della Bella, 16--. https://www.rawpixel.com/image/13978823/image-cartoon-person-treeFree Image from public domain licenseWilliam Barrett, aged 31. Stipple engraving by W. Walker after J. van Rymsdick. https://www.rawpixel.com/image/13998997/william-barrett-aged-31-stipple-engraving-walker-after-van-rymsdickFree Image from public domain licenseA colorful hot air balloon in the clear blue sky. Original public domain image from Wikimedia Commons https://www.rawpixel.com/image/3289771/free-photo-image-hot-air-balloon-adventure-aircraftFree Image from public domain licenseLesotho Africa 2013 Asset Collection TripImages from December 2013 asset collection trip to Africa. Original public domain… https://www.rawpixel.com/image/3382462/free-photo-image-2013-africa-apparelFree Image from public domain licenseEdward Jenner. Stipple engraving by Hoppe, 1803, after J. R. Smith, 1800. https://www.rawpixel.com/image/13971247/edward-jenner-stipple-engraving-hoppe-1803-after-smith-1800Free Image from public domain license