cellar door is considered to be the most beautiful combination of characters in terms of phonaesthetics (sound) in the English language. Semantics have nothing to do with this special characteristic. To me this highlights that, what some times tends to be common, average, and non remarkable, is indeed able to stand out among the rest because of some unforeseen attributes. Some might see a simple door to a cellar, where there lays a portal to a new, fascinating world.