With a colleague, Mona El-Naggar, I went to see for myself. We found Muhammad Said hanging out on a street corner. A skinny 19-year-old in a T-shirt and flip-flops, slouching on a red scooter, he volunteered to show us what had recently been built. The neighborhood is a rabbit warren of many blind, dirt alleys. Mr. Said led us down one alley after another, past mounds of rubble and collapsing wood-beam-and-brick houses, historic but decrepit. Some other young men appeared. They seemed to know Mr. Said. They began to follow us. There were no police around.

Mr. Said headed down a narrow passageway that dead-ended in the courtyard of an old house, a sunless air shaft strung with drying laundry. Why are we here? I demanded.

Many families live crammed together, Mr. Said answered. The people tearing down old places have been known to offer residents money to leave and new apartments, he said. “When you live together in a tiny room and someone offers you something better,” he wanted to tell us, “who would turn it down?” That was his point. This was not an outrage, but an opportunity — and a clash of interests among classes in a society being forced to legislate and reinvent itself.

The sad truth is that little of architectural quality has been built in Cairo in decades, no useful lessons learned from other big capitals, no progressive approaches to city planning embraced under Mr. Mubarak or the Muslim Brotherhood. Government officials promise urban improvements but peddle outmoded ideas about sweeping away informal neighborhoods: ridding the city of its poor while erecting skyscrapers to produce Dubai on the Nile for the well-to-do.

Many Cairenes who can afford it continue to flee to gated communities. Mr. Mubarak’s government built highways to speed the wealthy out of town. I visited an older one of these settlements, Katameya Heights, a golf resort with a little shopping village where the signs are in English and preposterous Roman villas hide behind walls of bougainvillea. Katameya Heights could be in Florida or Southern California. Since the revolution, real estate values have been rising in these gated developments, whose allure remains a life that is quiet, slow and green in a megalopolis that is none of those things.

At the same time, the protests in Tahrir Square, as Mohamed Elshahed, the young editor of Cairobserver, an online magazine, told me, “introduced thousands of people of different classes, from all over the city, to each other and to an urban alternative to the Cairo of suburban developments. The revolution was partly about rediscovering the city on foot,” he said.