On December 27, 1831, the H.M.S. Beagle leaves England on a survey mission to South America with the young naturalist Charles Darwin onboard. On September 15, 1835, the ship arrives at the Galápagos Islands and stays nearly a month. Darwin's observations of the islands' unique flora and fauna lead to his publishing in 1859 of The Origin of Species, an enormously influential book expounding the theories of natural selection and evolution.