Before the 1830s,most newspapers were sold through annual subscriptions in America, usually $8 to $10 a year. Today $8 or $10 seems a small amount of money, but at that time these amounts were forbidding to most citizens. Accordingly, newspapers were read almost only by rich people in politics or the trades. In addition, most newspapers had little in them that would appeal to a mass audience. They were dull and visually forbidding. But the revolution that was taking place in the 1830s would change all that.

The trend, then, was toward the "penny paper"— a term referring to papers made widely available to the public. It meant any inexpensive newspaper; perhaps more importantly it meant newspapers that could be bought in single copies on the street.

This development did not take place overnight. It had been possible(but not easy)to buy single copies of newspapers before 1830,but this usually meant the reader had to go down to the printer's office to purchase a copy. Street sales were almost unknown. However, within a few years, street sales of newspapers would be commonplace in eastern cities. At first the price of single copies was seldom a penny—usually two or three cents was charged —and some of the older well-known papers charged five or six cents. But the phrase "penny paper " caught the public's fancy, and soon there would be papers that did indeed sell for only a penny.

Crossing Phoenix, Arizona, are 180 miles of canals. In 1867, the city’s founding father, Jack Swilling saw the remains of irrigation (灌溉) channels wandering across the landscape. He realized that, centuries before, some society had farmed this desert. Soon after, Swilling began clearing the blocked canals to bring agriculture back to the region.

Three years later, Swilling and other pioneers met to consider names for their settlement. The top two were Pumpkinville and Stonewall. Luckily, English adventurer Darrell Duppa proposed a name inspired by the resurrection (复兴) of the canals. “A great race once lived here and another great race will live here in the future,” he considered. “I predict that a new city will spring, phoenix-like, from the ruins and ashes of the old.”

Gary Huckleberry, a researcher, said, “In the southwest, we have some serious issues to deal with in terms of water. The Colorado River is the main source of water for the southwest and it’s over distributed. We’ve got population growth and climate change. How are we going to deal with that? I think there’s something to be learned by looking at past societies who managed water for thousands of years.”

That great society was the Hohokam. Between 100 and 1450 AD, they constructed 1,000 miles of canals. As the Hohokam expanded their network, they constantly repaired, cleaned and diverted the canals. “It requires cooperation, because all the users of the water from that canal have to agree not only to construct it, but also to maintain it,” Henderson, a scientist, said. “Users would have to agree to certain conditions to keep the entire system going.” The Hohokam committed to sharing water and put themselves on timetables.

The Hohokam used canal irrigation for 3,000 years. “That, to me, is the definition of sustainable development,” Huckleberry said. “They learned how to sustainably farm, to manage water, to not destroy their soils in a way that is worthy and might give us insight into how we might deal with the current trouble. I think one of the key lessons is that you don’t put all your eggs in one basket.”

Cities usually have a good reason for being where they are, like a nearby port or river. People settle in these places because they are easy to get to and naturally suited to communications and trade. New York City, for example, is near a large harbour at the mouth of the Hudson River. Over 300 years its population grew gradually from 800 people to 8 million. But not all cities develop slowly over a long period of time. Boom towns grow from nothing almost overnight. In 1896, Dawson, Canada, was unmapped wilderness (荒野). But gold was discovered there in 1897, and two years later, it was one of the largest cities in the West, with a population of 30,000.

Dawson did not have any of the natural conveniences of cities like London or Paris. People went there for gold. They travelled over snow-covered mountains and sailed hundreds of miles up icy rivers. The path to Dawson was covered with thirty feet of wet snow that could fall without warming. An avalanche (雪崩) once closed the path, killing 63 people. For many who made it to Dawson, however, the rewards were worth the difficult trip. Of the first 20,000 people who dug for gold, 4,000 got rich. About 100 of these stayed rich men for the rest of their lives.

​But no matter how rich they were, Dawson was never comfortable. Necessities like food and wood were very expensive. But soon, the gold that Dawson depended on had all been found. The city was crowded with disappointed people with no interest in settling down, and when they heard there were new gold discoveries in Alaska, they left Dawson City as quickly as they had come. Today, people still come and go — to see where the Canadian gold rush happened. Tourism is now the chief industry of Dawson City — its present population is 762.