Deep in its well-preserved older neighborhoods, Charleston, S.C., almost seems to wish nothing had happened in the past 100 years. Ancient buildings (many dating back to the 18th century and some to the 17th) sit in the sun, harboring dreams of old money and adventures buried in the past. The most elaborate homes, along the spacious, no-longer-busy waterfront, look seaward on one of the East Coast's most beautiful harbors -- the site of Fort Sumter, where the Civil War began.

Downtown, the old houses are more crowded by current reality. They peer through ornate, antique wrought-iron fences as though wondering about the horseless carriages rolling by and the outlandishly dressed strollers: men who wear slogans on their T-shirts; women who shamelessly expose their ankles.

A few miles out of its downtown historic district (which has about 2,800 sites recognized by the National Register of Historic Places), Charleston could be Anywhere, U.S.A.: factories and office buildings, fast-food restaurants, self-service gas stations, shopping malls, nuclear-family suburban housing and motels comparable to the servants' quarters in the old homes downtown. A visitor has the impression that the old city hardly ever talks to the new city, except when there are goods or services to be ordered.

But for a few weeks every year, as May blossoms into June, another world encompasses old Charleston and new Charleston, bringing them together for a celebration of the arts. Outsiders -- tourists, singers, actors, dancers and chamber musicians -- come flocking in eager thousands. For these weeks, which grow a little bit longer with each passing season, the whole city becomes an enormous performing arts center.

"Spoleto" is the name attached to the busy happenings that began this weekend in Charleston. The Italian word can still sound strange on southern tongues, but in its 10th season and working with a multimillion dollar budget, the Spoleto Festival is an established and important part of the city's landscape.

Old Charleston and the affluent tourists come for opera, dance, chamber music and lavish black-tie parties. New Charleston may lack the cash to attend most of the international attractions, but it welcomes the tourists who pour that cash into its economy. More than half of the tickets sold, which number in the hundreds of thousands, are bought by people from outside South Carolina.

Less prosperous natives enjoy a wealth of free, mostly outdoor entertainment, presented under the blanket title of "Piccolo Spoleto" ("Little Spoleto"): jugglers and mimes wandering in the tree-lined streets and spacious parks; brass bands and jazz combos; art exhibits and a children's festival-within-a-festival. It is a street life as lively as what you see in "Porgy and Bess," an opera about life in Charleston a long time ago.

There was a lot of skepticism in the 1970s when Gian Carlo Menotti, founder of the "Festival of Two Worlds" in Spoleto, Italy, visited Charleston, fell in love with the city and announced: "This is the place for the Spoleto Festival in the United States."

The Italian festival is 20 years older than the American one, and the advantages of having two festivals with the same name and overlapping contents have become apparent in the past decade. The costs of sets and costumes for operatic and theatrical productions can be shared, and performances prepared for one venue have already been rehearsed, in a sense, for the other.

There is also mutual stimulation in tourist trade; Americans, enchanted with what they experienced in Charleston, are attracted to the European festival, as Europeans are (in smaller numbers) to the American one. Eventually, Spoleto may become a festival of three or four worlds. Lovers of the performing arts in Australia have been wooing Menotti to come down and start a festival there.

While he features all kinds of attractions in the festival (including some for which he will privately admit a lack of personal enthusiasm), Menotti's most memorable productions have been operatic -- and usually works that meant something special to him.

The opening night of the first Spoleto Festival in 1977 was a performance of his opera "The Consul," and he has given landmark productions of several other Menotti operas -- though not usually on opening nights. This year, he decided to mark the festival's 10th season with a new production of "The Saint of Bleecker Street," which ranks with "The Consul" in popular and critical esteem. It won a Pulitzer Prize for music after a successful run in the 1950s -- not in an opera house but on Broadway.

A few years ago, Menotti's blockbuster was "Antony and Cleopatra" by his lifelong friend and collaborator, Samuel Barber. This work was commissioned to open the Metropolitan Opera's new home when it moved to Lincoln Center in 1966, and with Leontyne Price heading a stellar cast it was a critical disaster.

Barber and Menotti worked together on revisions, but it was not until the Spoleto Festival production, using young and relatively unknown American singers, that the opera began to find its audience. That production is now available on New World Records, and Menotti's friend has received posthumous justice at last. Two years ago, Menotti used Spoleto, with spectacular success, for a similar rehabilitation of his own opera, "Juana, la Loca," which had not satisfied him in its original production. But not on an opening night.

The big opening night productions have oscillated between highly controversial efforts and carefully tailored crowd-pleasers. In 1983, the festival opened with a "Madame Butterfly" directed by Ken Russell in which the time was moved up to the eve of World War II, Butterfly lived in a house of ill repute and the final curtain came down on the atomic bomb exploding over Nagasaki. The following year, the opening night was completely conservative: "The Merry Widow" in a production that rocked no boats.

As a stage director (for his own work and that of other composers) Menotti has always said that (unlike Russell) he aims only to fulfil the wishes of the composer. In the case of "The Saint of Bleecker Street," he had no trouble figuring out what those wishes might be.

The festival has a new general manager this year: Nigel Redden, formerly director of the dance program at the National Endowment for the Arts. It is pure coincidence that this year's festival (planned before Redden came aboard) has more dance than any previous Spoleto Festival: eight dance companies, including the American debuts of the Scottish Ballet and the National Royal Ballet of Spain. But it may not be a coincidence that Redden's former boss, Frank Hodsoll of the National Endowment, agreed to speak at the festival's opening ceremonies.

Even more than opera, dance, plays and street performers -- perhaps more than Menotti himself, whose 75th birthday will be celebrated (about a month early) on the gala final evening of the festival -- the star of this year's Spoleto will be a cute little 3-year-old named Flora, the focus of a new attraction at the festival.

Flora is a baby elephant and the star of the Circus Flora -- a replica of an Italian traveling family circus that actually visited Charleston around 1830. With this addition, the festival seems to have closed the only significant remaining gap in its performing arts repertoire.