Sometimes seen as 'the American Shakespeare,' Mark Twain is probably the greatest playwright and author in American history. He was responsible for both 'The Adventures of Tom Sawyer' and 'The Adventures of Huckleberry Finn' among other great luminary works. He was also one of the finest thinkers of his era, maintaining an interest in new technologies and new ideas that lasted for his whole life.
Somewhat poetically, Twain felt that he both came into and left the world with Halley's Comet. He was born within two weeks of its closest approach to Earth in 1835, and died a mere day after its closest approach in 1910. He'd said in 1909 that he intended to die as the comet came close, and he was true to his word. This picture was taken in April 2010; the same month he died of a heart attack on the 21st.