Marrakech, the fabled "Red City" of the northern Sahara, is reason enough to go to Morocco, and when the two-week Folklore Festival is held there each June, the prospect of a visit becomes almost irresistible. Situated in a huge date palm forest in central Morocco, Marrakech is as close as Paris by air, but culturally it's as distant as the time of the Prophet Mohammed.

For the better part of 1,000 years Marrakech was one of the few safe and peaceful links between black Africa to the south and Moslem Africa to the north. The camel caravans that traversed the desert routinely stopped there, so it became a well-known center where ideas were traded as vigorously as items.

The ancient, free-wheeling character of the city is alive and well, and nowhere is it more noticeable than in the Djemaa El Fna, a sprawling expanse in the center of the city where each evening another act in the continuing theater that is Marrakech is played out to throngs of enthralled onlookers.

An hour or so before sundown, as the desert temperature begins its plunge, the Djemaa (which means the Place of the Dead) begins to fill with those who will soon be actors, performers and audience -- and during the early stages it is impossible to tell who, in biblical or western garb, will become what.

Soon the slow, tentative throb of dancers' drums begins to share the thick desert air with fading sunlight and the smoke and smells from a hundred charcoal grills on which small-time entrepreneurs prepare beef and lamb shish kebab. Suddenly the Djemaa booms to life with acrobats, snake charmers, storytellers, groups of musicians, magicians, fire-eaters, craftsmen, merchants, food sellers and fruit peddlers, jugglers, medicine men and crowds of onlookers. There are fortunetellers, free-form dentists, latter-day prophets and holy women, teams of three-card monte artists, brightly costumed water sellers and more.

Over the past 20 years I've been a frequent witness to the stark desert beauty that is Marrakech and to the gentle mayhem that is the Djemaa, and every night has been the same . . . yet refreshingly different. Some of the faces have not changed in all those years, and others are new, but the wonderful madness of this spontaneous carnival remains fascinating.

The National Folklore Festival -- this year's will be the 26th -- is a reflection of the more serious, modern and organized aspects of Marrakech. Conceived as a means of extending the tourist season, the festival has grown into the largest and most prestigious event of its kind in the Arab world, drawing visitors from all parts of the Middle East, Europe and the United States.

Eight years ago, in an effort to improve an already successful attraction, Mohammed Serghini and several other festival directors made an extensive journey throughout Morocco in search of new talent. They traveled from Tangier in the northwest down through Goulimine in the deep south and over to Taouz in the east; of the 1,200 groups auditioned, they photographed and tape-recorded the 600 they considered good enough to bring to Marrakech.

Because of the rich talent pool the performers are different every year, as is the show. The presentation is a 2 1/2-hour spectacle of horsemen, acrobats, dancers, musicians and singers that takes place under the cool night sky in the ruins of an ancient imperial palace. Almost as soon as one festival ends, planning begins for the next: A theme is selected, the groups are chosen, and the show is choreographed.

"We make absolutely no attempt to re-choreograph dances," says Serghini. "The dances are the people's thing and we do not tamper with them. We arrange the order in which the groups appear, and we set them up on the stage as backdrops for each other. We try to build an overall look, and we choreograph the finale, but that's it; what you see and hear is pure and authentic."

And it is purely and authentically stunning. The 50-by-20-yard stage, layered with dozens of intricately woven and colorful Moroccan carpets, stands inches above a 150-yard-long and 50-yard-wide reflecting pool within the red ocher ruins of the El Badii Palace. (El Badii, loosely translated, means the ultimate in splendor.) Large striped and pointed tents, like illustrations from "The Arabian Nights," face each other from stage left and right and are filled with groups of performers waiting for the show to begin. The enormous walls of the ancient ruin are reflected in the few yards of water that separate the stage from the seats.

After the audience is seated, the lights dim slowly, then die. The cool stillness of the desert night gives way to an explosion of sound and color as the night blazes white with electricity and two groups of performers dressed in flowing, traditional costumes -- accompanied by mounted horsemen, blaring trumpets and lilting reed flutes -- sing and dance up inclined ramps at either end of the stage and converge at its center.

Acrobats, barefooted and dressed in bright green trousers and red vests, somersault high in the air through the lines of performers as booming drum rhythms and crashing cymbals join the already soaring music.

The use of the word performers is, in a sense, both inaccurate and misleading. These are villagers, country people, farmers or peasants, and their costumes, music and dances are traditional and important parts of their everyday lives. It is said that the dances are hundreds and -- in some cases -- thousands of years old, and that the meaning of most of them has been lost, even to the dancers: "They hear the music," Serghini explains, "and they begin to move."

This is an authentic glimpse into the lives and culture of a country rich with tradition, spirit and diversity.

The best moment -- and there are dozens of very good ones -- is the last. After the final group exits the stage, the electric lights give way to crisp desert starlight, and one senses -- but does not clearly see -- a swirl of motion on stage. As a complete and eerie silence descends upon the ruins of El Badii, the lights suddenly blaze white again and the entire stage, packed from side to side with the rainbow of costumes of hundreds of performers, explodes with motion, music and song, and it is impossible to remain seated.

For more information: Moroccan government tourist office, 20 E. 40th St. Suite 503, New York, N.Y. 10017, (212) 557-2520.