6. Darwin and the Galapagos
Charles Darwin, the guy who came up with the idea of "natural selection" after studying variations among species of animals in the Galapagos islands, is exactly the kind of guy you might think had been visited by aliens once or twice. Maybe transmutation wasn't just seen between different species of finches and tortoises. What if the Aborigines of the Galapagos weren't Aborigines at all, but aliens who had colonized Earth thousands of years earlier and some had left the island to live on the rest of the planet? Or maybe the Aborigines had evolved more than the mainland humans and they had been what really inspired Darwin's theory of evolution? Either way, I'm sure the Doctor was involved somehow. Darwin is generally a universally recognized name and his studies are taught in both basic and advanced science and biology classes. It's another opportunity for an "alternative history" episode! Which, when done well (I'm thinking of the Van Gogh episode) is the best kind of episode.