Framed within a backdrop of faded industrial buildings and rusty water towers, Taco Flat looks like a relic of some bygone era. These rough-and-ready dwellings, untouched by the luxuries of electricity, sewage lines and cable connections, seem like an aberration in a country that has grown accustomed to newness, whether in the form of ever-faster Internet connections or the accelerating spread of big-box stores and single-family homes.

Much of the shock value of tent cities comes from the fact that they force one to do a bit of time travel, revisiting an atmosphere of social disorder that seems more fitting to a Gold Rush-era squatter camp, and a level of destitution that recalls the Hoovervilles of the 1930s. Even tent city residents themselves feel trapped in circular trajectories of history, doomed to lives shaped by the threat of lawlessness and the ever-looming peril of relocation.

Frankie Lynch, one of the self-proclaimed mayors of Taco Flat, has ancestors who fled Oklahoma during the Dust Bowl years, only to discover a new kind of poverty in the farmworker camps of California's Central Valley. Now he's drifting, too, unable to find the construction work that used to pay his bills.

"It's just going back to the same thing," said Lynch, 50. "I remember my grandparents and my dad talking about labor camps, and going town to town to work."

The folks who linger around Lynch's dwelling have a spectral resemblance to yesteryear's harvest gypsies. Their faces are drawn and sunken, pale as rock cocaine, twisted with coughs that suggest malnourishment. There's a soup kitchen called the Pov on the other side of the railroad tracks, but pride keeps some people from crossing over, and so does a rampant fear of muggings and stabbings.

Crime is a concern here -- according to county estimates, 41 percent of the homeless population has been incarcerated at some point or another -- but the greatest fear for most people is that they've lost their place in mainstream society, whether as a result of mental or physical illness, past mistakes or the whims of global capitalism.

In better times, they may have weathered their troubles, getting by with work in factories, call centers or construction sites. But now those jobs are gone, and many people wonder if they will ever come back.

Don Harmon, a carpenter, used to raise frames on commercial sites throughout Northern California. But last July, when all the building halted, he couldn't make his rent, and he ended up in Taco Flat with his 2-year-old son.

Like most of the stories one hears in tent cities, Harmon's would be hard to authenticate. But as he spoke, he held out his hands as if to prove his honesty. They were as worn-out as an old union membership card.

"I'm unemployed right now," said Harmon, his voice rising, "but I guarantee you these hands will work.  I will tear my hands up working, you know, to make sure my kid's gonna have what he's gotta have."

Tent cities have much in common with the squatter camps of the Great Depression, but to simply call them Hoover-villes is to ignore their complexity. To truly understand them, one must look at current trends in the developing world, where informal urbanism -- a form of "slum" development that takes place outside the conventions of city planning -- is now the predominant mode of city-making.

Informal urbanism, characterized by unauthorized land occupation, makeshift construction and a lack of public utilities, is how many burgeoning nations meet their housing needs. It thrives in places like Fresno, where poverty is endemic and there is a wide gap between rich and poor.

Rahul Mehrotra, a professor at the MIT Institute of Urban Studies and Planning, said there's a real kinship between Taco Flat and the squatter settlements of Mumbai, India, where he runs an architectural firm.

"It's really a reflection of the government's inability to provide housing affordably across society," Mehrotra said. Informal urbanism also thrives wherever people face exclusion from the mainstream markets for work and shelter, he added, whether for ethnic, economic or political reasons.

This can be seen in Taco Flat's large contingent of undocumented workers, who left their homes in Latin America to find work on the Central Valley's farms and construction sites. As borders tighten and immigration raids increase, the act of signing a lease has become more risky, prompting many to forego formal housing altogether.