A teacher comes out with a very large glass jar. He drops rocks in it until there isn't any more room. "Is it full?" he asks the students. They agree that it's full. Then he takes out a bag of gravel, which he pours in the jar. "Now is it full?" They agree that it's full. He takes out a bag of sand, which he pours in the jar. They agree that now, at last, it's full. He takes out a jug of water, which he pours in the jar. Okay, now it's full.

"What's the lesson?" he asks his class. A student answers, "There's always more room."

"No," the teacher replies. "It's that you have to put the big things in first."

A New Kind of City

Will the city disappear or will the whole planet turn into a vast urban hive?--which would be another mode of disappearance. Can the needs and desires that have impelled men to live in cities recover, at a still higher level, all that Jerusalem, Athens, or Florence once seemed to promise? Is there still a living choice between Necropolis and Utopia; the possibility of building a new kind of city that will, freed of inner contraditions, positively enrich and further human development?

- Lewis Mumford, The City in History