Cities became possible only when the development of agriculture made the supply of food more abundant and dependable. However, the new cities needed a way of stabilizing the food supply; seasonal crops had to be stored for later use. The Granary was designed for the storage and protection of food surpluses. The new agricultural techniques and the ability to store food meant that only some of the people had to work producing food for all. The rest could devote their time to dreaming up the alphabet, mathematics, computer games, and other important advances of civilization.