National Cancer Institute via Unsplash

Image by Unseen Histories via Unsplash

Detail of painting by Alexander van Haecken via Rijks Museum

Photo by Vinicius “amnx” Amano via Unsplash

Image by Geran de Klerk via Unsplash

Photo by Gabriel Dizzi via Unsplash

Photo by Peter Conlan via Unsplash

Via the Metropolitan Museum of Art

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Photo by Chris Charles via Unsplash

Photo by Markus Spiske via Unsplash

Photo by Angela Compagnone on Unsplash

Photo by Biodiversity Heritage Library via Flickr

Photo by Kensy Cooperrider

Photo by Jonathan Cosens Photography on Unsplash

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Image courtesy of Bill Thompson

Painting by Charles R. Knight via Staten Island Museum

Photo by Biodiversity Heritage Library via Flickr

Photo by Hadis Safari on Unsplash

Image courtesy of Alecia Carter

Photo by Alexander Sinn on Unsplash

Photo by Tim Foster on Unsplash

Photo by William Henry Jackson via Wikimedia Commons

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Photo by USAID Africa Bureau via Wikimedia Commons

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Photo by NASA via Wikimedia Commons

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Photo by Tanaphong Toochinda on Unsplash

Photo by Goban1 via Wikimedia Commons

Image courtesy of Matt Crosby

Photo by Joe deSousa on isorepublic.com

Photo by Dmitry Grigoriev on Unsplash