The European eel, Anguilla anguilla, is one of the strangest creatures nature ever created. Remarkably little is known about the eel, even today. What we do know is that it's born as a tiny willow-leaf shaped larva in the Sargasso Sea, travels on the ocean currents toward the coasts of Europe - a journey of about four thousand miles that takes at least two years. Upon arrival, it transforms itself into a glass eel and then into a yellow eel before it wanders up into fresh water. It lives a solitary life, hiding from both light and science, for ten, twenty, fifty years, before migrating back to the sea in the autumn, morphing into a silver eel and swimming all the way back to the Sargasso Sea, where it breeds and dies.