Phoenix  is called a “young” city so often that it’s easy to forget that there’s an entire ancient civilization buried underneath it. Native Americans have called the Sonoran Desert home for thousands of years, but the Hohokam people dug the first irrigation canals fed by the Salt River about 2,000 years ago. They improved and expanded the system over centuries using nothing but wood and stone tools, simple leveling devices, and their own labor. Some canals were as long as 20 miles and carried thousands of gallons of water through a complex series of main lines, laterals, and small ditches.
At its height around 1300, the system watered more than 10,000 acres scattered across most of what is now metro Phoenix. The Hohokam’s corn, beans, squash, and cotton crops supported as many as 50,000 people, making the Salt River valley one of the largest settlements in prehistoric North America. But after 1,500 years of growth, Hohokam society began a slow collapse, likely triggered by a combination of drought, environmental stresses, and war. By the end of 1400s, the people had abandoned their pueblos and canals for small farming villages scattered across the region.
Modern Phoenix wasn’t born until 1867, when a man named Jack Swilling passed through and saw that the Salt River Valley looked like a good place for farming. The broad, fertile valley was filled with desert grasses, mesquite, willow, and cottonwood trees, and best of all, the wide, winding river that flowed down out of the mountains to the northeast. So after the one-time army scout, gold miner, cattle rancher, and saloon owner returned home to Wickenburg, a mining town about 50 miles northwest of present-day Phoenix, he got financial backing from a group of local residents and organized a company to dig irrigation canals and establish farms in the remote valley.
It wasn’t long before he and the dozens of settlers who followed discovered that digging up the Hohokam canal system was an easier way to bring water to their fields than starting from scratch. So it was that an erudite settler named Darrell Duppa suggested they name their new town Phoenix , after the mythical bird that rises from its own ashes after being consumed by flame.
By 1900, the young town’s population had grown to 5,554 thanks to a long growing season and new railroads centered on historic Union Station downtown that took farmers’ crops all across the United States. Modern technology didn’t solve all their problems, though. Snowmelt and rain regularly sent the Salt River over its banks, including the worst flood on record in February 1901, which swelled the river to three miles wide in some places, wiping out crops, houses, and the all-important railroad bridge.
The brand-new territorial capitol west of downtown was inundated, too, destroying many early records. Luckily, President Theodore Roosevelt was ready to ride to the rescue with a bold plan and several million dollars.
Roosevelt tasked the newly formed federal Bureau of Reclamation with building a hydroelectric dam on the Salt River in 1911 to control flooding and generate electricity. It was the first project the new agency tackled, and though it tamed the free-flowing river by diverting the whole flow from its banks into an expanded canal system, it led to one of the city’s first big boom periods.
With an economy fueled by the “Five C’s”—citrus, cotton, cattle, copper, and climate—Phoenix’s population mushroomed to nearly 30,000 people by 1920, then added almost 20,000 more by 1930, matching the Hohokam’s previous record of 50,000 inhabitants in just 50 years. The boom had barely begun, though.
Following World War II, returning soldiers—many of whom had trained at the airbases that sprang up around Phoenix thanks to its sunny, flying-friendly weather—flocked to the area and its burgeoning aerospace industry. As air-conditioning became widely available and early technology-manufacturing companies also moved here in search of cheap land, the population grew past 100,000 by 1950 and neared an almost-unimaginable 440,000 by 1960.
Today, some 1.5 million live in Phoenix , making it the fifth-largest city in the nation behind New York City, Los Angeles, Chicago, and Houston. Growth has come with a price, however. Many residents see pollution and the destruction of pristine desert sapping their quality of life as suburban sprawl forces them to spend hours commuting or going about everyday tasks. But the same spirit that drove Phoenicians to build a metropolis in less than 150 years is pushing them to dream up new solutions, and it’s anyone’s guess what seemingly impossible feats the residents of this dynamic city will tackle next.