In 2009 two important commemorative events coincide—the bicentennial of Charles Darwin’s birth, coincidentally on the same day as Abraham Lincoln’s, and the sesquicentennial of publication of Darwin’s pioneering work On the Origin of Species by Means of Natural Selection. Universities and natural history museums around the world are celebrating Darwin’s achievement throughout the year. Here we take a fresh look at the voyage that turned Darwin into one of science’s greatest thinkers.