The Final Countdown

S1 E4: In 1831, the young naturalist Charles Darwin set sail on the most important journey ever made. Over the course of five years, Darwin circumnavigated the earth on the clipper Beagle, making discoveries that changed our ideas of time, space, chance, sex and nature. Almost 180 years on, his great-great granddaughter Sarah Darwin and British author Redmond OHanlon repeat this epic expedition...