The separation between the child's world and the adult world is unknown in traditional societies. In simple villages, children spend their time alongside farmers in fields, side by side with people who are building houses, close, in fact, to all the daily actions of the men and women around them. By contrast, modern cities are so dangerous that children cannot be allowed to explore them freely – life is so enormous and dangerous that children can't be left to roam around. There is constant danger from fast-moving cars and trucks and dangerous machinery, as well as the danger of assault or kidnap and, particularly for smaller children, the danger of getting lost. The obstacles to exploration inhibit the maturation process by depriving the child of opportunities to acquire self-confidence and to interact with the real, dynamic world of change, risk and reward surrounding him.