1835: Born Nov. 30 in Florida, Missouri.

1839: Clemens family moves to Hannibal, Missouri, a port town along the Mississippi River. Fascinated by the river, young Samuel aspires to become a steamboat pilot.

1847: After his father, John Marshall Clemens, dies, Samuel, 12, leaves school and begins an apprenticeship with the publisher of the Missouri Courier to help support the family.

Photos courtesy of Mark Twain Collection (#6314), Clifton Waller Barrett Library, The Albert H. Small Special Collections Library, University of Virginia Library.