Luanda is a boomtown. Oil brings in more than $3 billion a year, and the major companies plan to spend tens of billions more in the southwest African nation over the next five years. Huge new deep-water finds could make Angola the continent’s leading oil producer in a decade. It already supplies 8 percent of the United States’ oil, more than Kuwait. Not even the brutal civil war waged by rebel leader Jonas Savimbi for the last quarter century can explain why nothing seems to trickle down.

But the consequences are pain-fully obvious. Down the block from the glitzy local headquarters of the French oil giant TotalFinaElf, street children make their homes in four abandoned cars. They’ve removed the seats and covered the vehicles with pieces of plastic, cardboard and sheet metal. One car has sprouted a second floor. The “residents” carry parcels for shoppers at a nearby supermarket, and cook their food in a fire among the rusting hulks. Two blocks away, another group of kids have set up housekeeping in the sewer. They climb down a storm drain; when it rains, they scurry out quickly.

Downtown, the desperately poor and the fabulously rich live as neighbors, sharing only air laden with the scent of rotting garbage. Squatters have taken over the 12th-floor shell of one building. You can see them from atop a nearly identical skyscraper, headquarters of an Angolan bank, with the same splendid view of the harbor. At a restaurant on its 15th floor, you can buy a bottle of Moet & Chandon champagne for $400.

But the gross differences in fortune don’t seem to bother Angolans at the top of the food chain. The country’s latest scandal: a five-day private visit to Brazil by First Lady Ana Paula dos Santos. The Brazilian press chronicled her huge tips to the staff of a five-star hotel. She reportedly went on a shopping spree of at least $75,000. Brazilian papers noted that the sum equaled the annual budget of a microcredit program Mrs. Dos Santos runs for poor Angolan women.