Perched above the Mississippi River, Natchez lies dreaming under a canopy of Spanish moss, the most elegant patch of living antebellum mansions in the South -- Savannah and Charleston not excluded.

Decades after the invention of the bulldozer and the lucrative parking lot, survival of the city's architectural treasures seems a miracle. Unlike many American cities, the central district is not a decaying urban problem, but a complex of perhaps 40 or 50 blocks of antebellum structures ranging from white-columned brick mansions of the aristocracy to tidy cottages.

For 40 years I have been treating myself to a nostalgia fix in Natchez, and I have come to know those house-proud burghers. As much as the dwellers in the great mansions, my friends among the cottages have ferocious pride in the yards and houses left by the long-vanished gentry. All householders cling to names handed down from the Romantic Age of the 19th century -- The Briers, Cheroke, Elmscourt, Magnolia Vale. The most modest cottage posts a sign at the sidewalk to let the visitor know what great-great-grandma called the place when they built it.

Everybody in the town's core keeps lawns and gardens like showplaces, for that is indeed what they are. A householder would as soon chop off a leg as cut down a living tree, so that the town lies in the dappled shade of centuries-old oaks, magnolias and pecans. A walk down a Natchez street brings on a curious feeling of de'ja vu, paradoxically for a time and place you've never seen except in Currier and Ives prints or romantic movies.

It was not by supernatural intervention that history survived in Natchez; it was by the canny planning of a band of improbable developers. For half a century, a circle of southern belles has treated history as a hot commodity and packaged it shrewdly to save the river-port town from ruin.

Founded in 1716 and a veteran of government under six flags (French, English, Spanish, American, the sovereign State of Mississippi, and Confederate), Natchez is probably the oldest continuing settlement in the Mississppi Valley, older even than New Orleans. During its first 150 years of existence, Natchez rolled in money as a cotton port and trade center for the new frontier. It is an article of faith among the city's residents that during most of the 19th century half the millionaires in North America lived in Natchez. But Reconstruction began the downward slide and, during the Great Depression when cotton was selling for 5 cents a pound (one-tenth of today's price), Natchez fell on hard times.

Nevertheless, the planter aristocracy had somehow preserved the material trappings of the 19th century cotton boom -- the neoclassical columned mansions, the furniture brought up the river by steamboat, the artworks imported from France. But some of the ladies, under their elegant exteriors, wore lingerie made of flour sacking.

That's when a few of those women calculated that if their husbands couldn't sell cotton, their wives were going to have to sell Old South Nostalgia. They scraped together a few dollars and dressed up their houses to throw them open to the public -- hoping that modern romantics would pay hard money to see how the quality folk lived in Scarlett's day.

The gamble worked beautifully; 150,000 visitors a year now ramble through the old quarters. Though it has a population of only 25,000, Natchez has five historical districts, nine landmark buildings, and a stunning total of 82 houses on the National Register of Historic Places. More than 500 antebellum structures survive, 100 are imposing enough to classify as antebellum mansions, and most are regularly open to the public -- especially during annual Pilgrimages. From a list of the most famous, as many as 20 and no fewer than four houses rotate the duty of staying open daily. Several agencies and organizations offer guided tours.

Since 1932, Natchez has been making a special parade of its monuments during Pilgrimage, a month-long social season from early March to early April when many antebellum houses are open for tours. Yards and gardens are aflame as the azaleas are at their peak. The nights are lively with Confederate Pageant, Southern Exposure, and Moonlight and Magnolias theatricals. Visitors throng, so hotel prices jump, of course, and the money rolls in. And the women have started an annual two-week Fall Pilgrimage beginning the first Saturday in October.

A sampling of the houses open during Pilgrimage -- and often year-round (accommodations are indicated, where available):

Dunleith (1856) is a neoclassical mansion that looks like a Greek temple with colonnaded two-story galleries wrapped around four sides. Garden enthusiasts travel miles to take in the massed tulips, planted two inches apart, which bloom early in Pilgrimage month. Visible from the street, the mansion is one of the principal glories of Natchez architecture. (Overnight accommodations.)

Monmouth (1818) has a square-columned portico and houses a Civil War museum in converted servants' quarters. Monmouth once was the home of Gen. John Quitman, a Mexican War hero who resigned as governor of Mississippi to escape indictment for organizing a filibuster on Cuba and who may have died from poison given to him at a banquet for President Buchanan. (Bed and breakfast.)

Melrose (1841) furniture may look familiar because the rosewood carvings were copied by the Gorham Silver Co. for the classic Melrose pattern of sterling flatware.

Stanton Hall (1857) belongs to the Pilgrimage Garden Club and is probably the best-known of the city's mansions. (Accommodations during Pilgrimage.)

Peter Crist House (1790) is of West Indian design. The detached kitchen, kept separate from the big house to prevent the spread of fire during the days of wood ranges, is one of two surviving in Natchez and still used as a kitchen.

Rosalie (1820) stands on the site of Fort Rosalie where the Natchez Indians in 1729 massacred the entire French settlement. It now belongs to the Mississippi chapter of the Daughters of the American Revolution. Rosalie came into being because Peter Little in 1806 had married a 13-year-old girl whom he sent north for education the day of their wedding. When she returned as a grown woman, he presented her the newly finished house.

The Parsonage (1840) was also built by the infatuated Peter Little as a gift for his wife, so that she could house visiting Methodist preachers. The Parsonage is a far grander structure than most circuit-riding Methodist preachers of the day were used to -- or than the ministers of today are, for that matter.

The Burn (1832) was built by one mayor and now houses Mayor and Mrs. Tony Byrne. During the Civil War, the Union artillery made its headquarters here and chopped down the shade trees and orchards for firewood. Time has healed the landscape but not the memory. (Bed, breakfast and swimming pool.)

The Elms (1798) shows influence of the Spanish occupation in a wrought-iron stairway imported possibly from Spain or more likely from Portugal.

Twin Oaks (1810) for three years sheltered Mother Cornelia Connelly, founder of the Society of the Holy Child Jesus. (Guest cottage.)

Myrtle Terrace (1850) was the home of Tom Leathers, captain of the steamboat Natchez who lost the famed race to the Robert E. Lee because, his supporters contend, he tied up rather than risk his passengers in a fog. (Guest cottage.)

Connelly's Tavern (1798) is of West Indian architecture. It is a historic project of the Natchez Garden Club. During early years, the tavern was the center of the city's social life, and here Andrew Ellicott raised the American flag to defy Spanish authorities who were sluggish about leaving after America had claimed the site.

Green Leaves (1846) is well named, for it is shaded by immense live oaks and magnolias and landscaped with magnificent camellias and azaleas worth a long detour to see during late winter and early spring -- Pilgrimage time.

D'Evereux (1840) is pure Greek Revival and one of the handsomest architectural monuments in a field where the competition is ferocious.

Just outside of town is the eccentric Longwood, laid out as a quasi-Moorish octagon but never completed because the workmen, on hearing of the outbreak of the Civil War, dropped their tools and trooped off to join the colors. The southern guides at Longwood rarely mention that the patriots were all from Philadelphia and joined the Union Army. Nobody has picked up the tools, incidentally, and they are lying on the top floor awaiting the return of their owners.

That's only a sampling. Just to add the few more that offer overnight accommodations: Dixie (1795); Elgin (1800); Hope Farm (1774), once the home of a Spanish governor and of the founder of the Pilgrimages; Linden (1800); Propinquity (1790); Shields Townhouse (1860); Silver Street Inn (1840), once a bawdy house; Texada (1792), once the territorial legislative hall, and Turkey Feather (1835).

A dazzling display of what makes Natchez work came my way when I was doing research for an article on the Natchez Trace. I called on Roane Fleming Byrne, universally addressed as "Sweet Auntie." I interviewed Mrs. Byrne because she was the principal piston in the machine that drove half-a-dozen reluctant federal administrations into piecing together a Natchez Trace National Parkway.

Ravenside, her home, was a Victorian affirmation of the gentility of antimacassars, convent needlework and double draperies. But tucked into one corner was a "war room," which, by no accident, was the bar. Around three walls was an engineer's strip map of the proposed 500-mile parkway. Scrawled on it, sometimes in an uncertain hand, were dates of promised extensions and alterations, crayoned in by visiting engineers and politicians who had been mesmerized by their hostess into guaranteeing projects far beyond accepted budgets.

She offered me a bourbon from the bar. It was 8 in the morning.

"Ordinarily, I don't offer a drink before 9 a.m.," she said, "but for a writer of your stature, I am forced to make an exception."

And I wasn't even a member of Congress.

Natchez is the product of people like Mrs. Byrne, southern women of velvet charm and iron will.

Even among the major restaurants, history counts. Broadway Station is in an old converted railroad depot, the Carriage House is at Stanton Hall, and the Post House is in King's Tavern, possibly the oldest structure in the entire Natchez territory. The menus run heavily, of course, to southern dishes like catfish and pecan pie.

Two restoration projects have recently added major historical sites. Defunct Jefferson College in nearby Washington supposedly once had Audubon on the faculty and Jefferson Davis among the students. Aaron Burr was tried for treason by a grand jury under immense oaks on the school's grounds and dismissed because the prosecutor could find no evidence more damaging than possible evil thoughts. In 1815 Andrew Jackson's riflemen camped there on their way home from the Battle of New Orleans.

The other new restoration is at the Fatherland Site of the Natchez Indian tribe. The last survivors of the mound builders, the Natchez Indians remained a powerful tribe after the arrival of the white man. The Natchez made a terminal error in 1729 when they slaughtered the French at Fort Rosalie, as Natchez was then called. From the Gulf Coast, the French governor Bienville sent an expeditionary force that shattered the tribe. Hundreds of Indian captives, including the chief, finished their lives as slaves in Caribbean cane fields.

To get a splendid view of the river for perhaps 20 miles in both directions, visitors climb a bluff to The Briars (1812) where Jefferson Davis married in 1845. Or they walk a few yards to the Ramada Inn's lawn for a view up river across the bridge. For flood control, the batture -- the land between the levees -- is deliberately left as a wilderness so that a view up river from the bluff looks the same as it did to the Natchez Indians before the first white man came. Except of course for the bustling river traffic, the towboats pushing immense rafts of barges loaded with grains and gasoline.

Just upstream from the bridge lies the waterfront of the city, perched overhead on a bluff. Once the waterfront flourished as Natchez-Under-the-Hill, the most wicked hellhole in the western world catering to the deplorable appetites of tough river boatmen. After the steamboat trade declined, for decades the one street left of the riverfront slumbered; but recently entrepreneurs have opened restaurants, shops and saloons for visitors, including steamboat passengers from scheduled stops of the Delta Queen and the Mississippi Queen.

The keepers of nostalgia's flame welcome the steamboats, of course, for they add a splendidly authentic touch to the historic landscape. When either of the paddlewheelers is in, the waterfront is a lively place. Musicians from the boats jam for hours in the saloons. When both boats tie up at once, as sometimes happens, and passengers contend over who is riding the better boat, Natchez-Under-the-Hill captures an ersatz raffishness reminiscent of the bad old days -- perhaps not so thrillingly dangerous, but it will do.

(For further information: Natchez-Adams County Chamber of Commerce, P.O. Box 725, Natchez, Miss. 39120, 601-445-4611.)