How can they do so? People must be resilient, and government must help.
Consider the case of London. On September 2, 1666, 350 years ago today, the Great Fire of London began. Abetted by a dry summer and a strong easterly wind, the fire consumed four-fifths of the city, leveling 13,000 houses and most of London's shops, government buildings and churches over the course of three days. The heat was so intense that cellars still burned six months later.
The fire's slow progress kept down the immediate loss of life: reports varied from no fatalities to a handful. Conditions for the 75,000 refugees who camped in suburban fields were undoubtedly more lethal than the fire itself.
The residents of London came in for much criticism. They had long ignored building codes and laws that would have made buildings fire-resistant and would have kept combustible materials off the streets. As the fire raged, nearly everyone set about protecting his or her own property, rather than stopping its spread.
Local government fared no better. After being roused from bed to view the first flames, the feckless mayor of London declared the fire so small that "a woman might p--- it out," and went back to sleep. He later refused to issue orders to create fire breaks by pulling down buildings because he feared that the owners might sue him.
The destruction of Europe's second-largest city was an economic as well as a social catastrophe. Much of London's wealth was tied to property: the rich invested in leaseholds, then sublet the properties to obtain a return on their money over time. It was not unusual for a property to be sublet six times, with each new landlord taking a small profit on the sublease. In today's money, well over £1 billion (in leasehold value) went up in smoke.
The poor and middling classes were also affected. Leases required the tenants to rebuild, even when the fire was not their fault. Fire insurance did not exist, and courts were merciless in enforcing covenants. Workers had no way to make a living. Londoners faced financial ruin.
Rebuilding London was by no means a given. Members of Parliament -- especially the country gentry -- balked at financing the effort. Doubtful of London's future, tradesmen decamped to London's suburbs and other towns. Four months after the fire, the diarist Samuel Pepys lamented, "The City [is] less and less likely to be built again."
Of course, London did rebuild. "Resilience" is a little-discussed aspect of human nature, at least until a catastrophe like Hurricane Katrina forces people to dig deep. Psychological literature is divided over whether resilience is a personality trait, a cognitive process or a learned skill.
Whatever it is, some people have great capacity to absorb shocks to their ordinary way of life and encounter new experiences while maintaining the structure and identity of their prior lives. Not everyone in London was resilient, but enough were.
One of the Great Fire's lessons is how government can foster resilience. Charles II refused to let Parliament disband until it passed legislation to aid London.
Parliament levied taxes to construct government buildings and purchase land for widened streets. In one of the first instances of successful urban planning, Parliament enacted, and local officials enforced, strict building codes. It also created a court, radically user-friendly even by modern standards, to extend lease terms and reduce rents, giving tenants a financial incentive to rebuild.
Eventually, Parliament eased medieval restrictions on citizenship, bringing in waves of tradesmen eager to repopulate the city.
The specifics of London's recovery differ from those of modern disasters like Amatrice, but the need for initiative by private citizens is universal. After the Great Fire, entrepreneurs started selling fire insurance, and banks soon emerged as a safe alternative to keep capital. A medieval city soon became the world's financial center.
Likewise, government must be flexible and responsive, adopting new rules that aid recovery but also removing laws that hinder the creative efforts of residents to place the local economy on a new footing.
While surveying flood damage in Baton Rouge, President Obama made an essential point. Resilience requires patience, and government must be there for the long term.
It took 10 years of private and public cooperation to rebuild London. Aside from Christopher Wren's churches, little of the rebuilt London survived further urban renewal over the following century. But physical structures did not matter. In the face of catastrophic destruction the idea of London had survived.