Once upon a time there was a wide river that ran into the ocean, and beside it was a little city. And in that city was a wharf where great ships came from far countries. And a narrow road led down a very steep hill to that wharf, and anybody that wanted to go to the wharf had to go down the steep hill on the narrow road, for there wasn't any other way. And because ships had come there for a great many years, and all the sailors and all the captains and all the men who had business with the ships had to go on that narrow road, the flagstones that made the sidewalks were much worn. That was a great many years ago.