Charles Darwin (1809–1882) left medical school in Edinburgh because he could not bear to watch operations, and studied at Cambridge to become a clergyman. Instead, at twenty-two, he joined the five-year voyage of HMS Beagle, described in The Voyage of the Beagle, which gave him the observations of a lifetime.
Back in England he worked for twenty years at his country home in Kent before a letter from the naturalist Alfred Russel Wallace, who had reached the same idea, pushed him to publish On the Origin of Species in 1859. He went on to write The Descent of Man and books on barnacles, orchids and earthworms, and was buried in Westminster Abbey.