Figs show how symbiotic visitors can transform a flower into something rather different - a swollen enclosed garden. The inside of a fertile fig typically looks like this:
Over evolutionary time, coevolution with the enclosed wasps has transformed the fig's flower. This transformation acts as a parable for what has been happening with the human cranium for the last three million years.
The story of the fig and its wasp is told in a relatively recent documentary "The Queen of Trees". A preview is available - in the form of these videos:
It may well be pirated, but currently the whole documentary is available on YouTube here.