For centuries in Europe, “black swan” was a phrase for something impossible, because all known swans were white. Until, at the end of the seventeenth century, Dutch explorers arrived in Australia… and there they were. The black swan has almost entirely black plumage and an intense red bill with a white band. But it holds a surprise: when it flies, it reveals the white feathers of its wings, which stay hidden at rest. Male and female form stable pairs and share the work: both incubate the eggs and look after the cygnets, which sometimes travel comfortably on their parents’ backs. Today it is the emblem of the state of Western Australia. And its name is still used to describe the unexpected.