Charles Darwin was a prominent English biologist and naturalist. He is most famous for is theories on natural selection and population evolution. When Darwin was a young adult, he took a five year voyage around the world on the HMS Beagle. In particular, the ship travelled along most of the coastline of South America (including the Galapagos Islands) and also made stops in Australia and South Africa. Darwin travelled on the land at all of these places and collected numerous animal specimens, fossils, and made extensive notes on everything he saw. The variety of animals that he saw on the different islands of the Galapagos versus mainland South America and also the unique animals he saw on Australia eventually led him to develop his theory of natural selection and the evolution of the species when he returned to England.