Charles Darwin may be a household name now, but we haven't always had the theory of natural selection. On November 24, 1859, he published On the Origin of Species as a culmination of nearly three decades of research after his journey on the H.M.S. Beagle. Happy 155th anniversary of On the Origin of Species!
Now it's easier than ever to understand Darwin's original thoughts on evolution with digital archives made public by the Darwin Manuscripts Project. The project, founded in 2003, is a collaboration between the American Museum of Natural History, Cambridge University Library, and other organizations to digitally archive all of Darwin's works.
Today, the project is about halfway finished. You can look through 16,000 images of Darwin's drawings, annotations, and writings on evolution. By 2015, the archives will be expanded to 30,000 documents spanning from 1835 to 1882.
Check out the gallery below to see some of the original artwork from the books and from Darwin's personal collection.