In 1831, Charles Darwin set sail on one of the greatest scientific journeys ever made. Darwin circumnavigated the Earth on the clipper ship, The Beagle, stopping along the way to observe flora, fauna, and the natural scene. He made discoveries that changed our ideas of time, space, chance, sex and nature. Almost 180 years later, his descendant Sarah Darwin and British author Redmond O'Hanlon repeat this epic expedition to find out how Darwin's world has changed.