Artist's concept of a time in the future when large populations are centered in a relatively small area. Cities or population hubs tend to grow up instead of out. Mass transit exists between the population hubs and travels through transportation tubes which help control pollution and protect riders from radiation which is the result of a degrading environment. Very few residents have their own vehicles because of the expense and those few that exist must also travel within the transportation tubes. It is a high-tech world created to make life possible in an increasingly hostile environment. In the foreground, a crew in a rover monitor air and soil in the world outside the domes.