BATRIK, Pakistan — On the northwest tip of Pakistan, bordering Afghanistan's Nuristan province, the inaccessible Chitral district has been thought to be a possible refuge of Osama bin Laden. Amid the high peaks of the Hindu Kush range and its narrow valleys, it's easy to dodge through secret mountain routes between Pakistan and Afghanistan.

Chitral is also the home of the Kalasha, a pagan culture that's lived in the area for 2,000 years or more, now boxed in by an increasingly militant Islam. Thinly populated, Chitral covers 5,800 square miles, with war-torn Afghanistan to the north and west and the extremist strongholds of Swat and Dir to the south.

According to locals, bin Laden lived with a Kalasha family in Chitral for some time during his first Afghan jihad, against the Soviet Union in the 1980s. With his now much more severe ideology, the al-Qaida leader wouldn't be able to easily live among these polytheistic people, whose men and women mix freely.

Last month, the Kalasha celebrated their spring festival, Joshi, with a verve and passion that few cultures match, ancient or modern. Men and women danced tirelessly to a pounding, primeval drumbeat, haunting singing and rituals so old that their meaning is almost lost.

COLORFUL, SPIRITUAL

The Kalasha women wear long black dresses with vividly colored embroidery, their hair in long plaits and regal headdresses decorated with shells. Garish belts and layers of brightly colored necklaces add to their exotic appearance. This isn't a special costume for Joshi, it's what they wear every day.

Dots and tattoos are painted on their cheeks. With improbably pale skin and piercing light eyes, any of a dozen girls at each festival gathering could adorn the cover of National Geographic magazine like the famous 1985 photo of the Afghan girl.

The Kalasha men are losing their customs more quickly. They no longer wear their age-old clothing of tight trousers and heavy knee-length coats. Instead they've adopted Pakistan's male uniform of the shalwar kameez, a loose-fitting long shirt and baggy trousers.

There are only about 3,000 Kalasha left now, pushed into three tiny valleys within Chitral by the advancing tide of settlers and spread of Islam. There, they struggle to keep their faith and way of life alive.

May's Joshi showed that Kalasha traditions remain strong and utterly unlike anything in the rest of Pakistan.

"This is a religious ceremony, it celebrates spring. It is not a festival. It is much more than that. There is a spiritual meaning behind it," said Tach Sharakat, one of the few members of his Kalasha community to receive a foreign university education.

WINE AND SONG

One legend has it that these are the descendants of the army of Alexander the Great, which invaded India in the third century B.C. No one really knows their origins. Their religion may be one of the early beliefs of the Indo-Persian area, embodying an early Hinduism and pre-Zoroastrian faith. They are known as the Kafirs — "infidels" — to most Pakistanis, but call themselves Kalasha or Kalash.

Sharakat thinks he's in his late 20s, but as the Kalasha don't record birth years, he and the other members of his culture can only guess at their ages.

They don't have a written language, so their knowledge has been handed down by word of mouth. That's why celebrations such as Joshi are so important to the Kalasha.

They're a way of passing on their culture to younger generations. While it's easy to be mesmerized by the joyous dancing, the important message of the dance is coming from within the circle, where old men in long golden coats sing and chant the Kalasha beliefs and narrate their history. The dancers then take up the song.

These are a people who love drinking wine — banned in Islam — and who can choose their husbands or wives freely, whereas arranged marriages are the norm in Pakistan. The women make no attempt to hide their faces and dance with gaiety in public, a sight now so rare in increasingly conservative Pakistan that it's shocking to most of their countrymen.

UNEASY TOURISM

Bewildered Muslim tourists from other parts of the country, typically groups of men, stared at the recent Kalasha festivities, seemingly not quite grasping that this too is a religion. Islamic culture dominates Pakistan and religious minorities are few. It seemed that it was lurid tales of the Kalasha women that had brought the tourist men here, confusing the women's freedom for free love.

"We marry who we like," said Gul Shaheen, a young teacher. "And there are no class distinctions in the marriage match. It does not matter if you are rich or poor. If a girl is ill-treated, she can leave for another man."

The Kalasha dance is a curious sidestep, performed by groups of men or women who stand shoulder to shoulder, arms linked. They skip in a large circle around the storytellers. Loud catcalls and whistles punctuate the singing, as does a theatrical ha-ha-ha laughter. All the time, the hypnotic drums pound, the sound carrying across the valley and into the surrounding peaks of the Hindu Kush.

According to one account, the dance is meant to frighten away snow leopards; the mountains of Chitral are one of their last remaining habitats. The whistles chase off snakes, while the laughter is for keeping away bears.

Said an elderly Kalasha woman, Jansabi, who has only one name: "Before, it (the dancing) was very beautiful. Now everyone just runs around."

The three-day festival moved from valley to valley, with the Kalasha gathering in one place each day for the singing and dancing. One reason the culture has survived is its geographical isolation.

This year, for the first time, Pakistan's tourism authority promoted Joshi, drawing unprecedented crowds. Although no more than a few hundred outsiders were present at any one time, the peering, leering crowd clearly made the Kalasha uneasy.

Much more serious disruption is to follow, from the opening of a simple land route into Chitral through the Lowari Tunnel, which should be complete by the end by next year.

"It would be a great pity to lose one more ancient tribe," said Athanasios Lerounis, a Greek aid worker whose nongovernmental organization has set up a museum for the Kalasha in the Bumboret valley. "People must behave like visitors to an open, living museum. This is not just a place to have fun."