Skulls: twenty-one skulls or parts of skulls arranged in four rows. Photograph. https://www.rawpixel.com/image/13962177/skulls-twenty-one-skulls-parts-skulls-arranged-four-rows-photographFree Image from public domain licenseCyborg sticker skull representation accessories accessory. https://www.rawpixel.com/image/14217766/cyborg-sticker-skull-representation-accessories-accessoryView licenseRunderschedel, 1825 (1825 - 1826) by Daniël Veelwaard II and Haatje Pieters Oosterhuis https://www.rawpixel.com/image/13782845/image-paper-cartoon-trophyFree Image from public domain licenseGeorge Combe lecturing on phrenology to a mixed audience in his Edinburgh home; presented as a monkey with a phrenological… https://www.rawpixel.com/image/14020901/image-cartoon-face-personFree Image from public domain licenseSarawak: preserved and decorated human heads taken and strung up by Sea Dayaks. Photograph. https://www.rawpixel.com/image/13992665/photo-image-face-plant-peopleFree Image from public domain license