CANYON DE CHELLY NATIONAL MONUMENT, Ariz.— You can't drive around on your own in this canyon or hike where you please. And you should ask permission before taking pictures of the Navajo Indians who still live and farm here.

But these rules are worth observing in order to spend a few hours in Canyon de Chelly National Monument, which occupies a unique place in the heritage of American Indians.

Canyon de Chelly is located entirely within the Navajo Reservation. You can drive the park rims by yourself and hike on one trail, the White House Trail. But the canyon interior can only be explored in the company of a Navajo guide, whether on foot, on horseback or by Jeep.

The park is celebrating its 75th anniversary in the national park system this year. Yet its history goes back much farther in time, from 1,000-year-old cliff dwellings to drawings etched on rocks, some from the 19th century and others much older.

And while summer is peak season for many destinations in the national park system, don't hesitate to plan a visit here this fall. "In October, the cottonwood trees turn golden," says Dave Bia, a Navajo guide who leads Jeep tours from Thunderbird Lodge, the only hotel inside the park.

But the park's human history, rather than its natural beauty, is what draws most visitors. Anasazis, who are believed to be the ancestors of modern Hopi and Pueblo Indians, built intricate homes here between A.D. 1100 and 1300, using adobe bricks carved from the soft red sandstone. Some of the dwellings were up to five stories high and housed 30 to 40 families. Several sites include kivas — large round rooms dug into the ground, used for ceremonies.

The tours also take you to sites in the canyon where conflicts took place between Indians and whites — from 16th-century Spanish conquistadors to 19th-century Americans like Kit Carson. Carson led a detachment of the U.S. cavalry here in 1864, forcing 8,000 Navajos on the "Long Walk," a 300-mile march to Fort Sumner in New Mexico.

Bia pointed out a towering rock wall where Indians tried to hide, but said they were forced to choose between starvation and coming out after white soldiers destroyed the crops they relied on for subsistence. Four years later, they were allowed to return to their homeland.

About 80 Navajo families still live in the canyon, many in traditional hogans with six or eight sides. "From the 1800s on, there has been farming going on here — corn, squash, melons, beans, alfalfa, peaches, apples, pears and plums," said Bia.

The tours also take visitors to several spots in the park where Indians sell jewelry, crafts and snacks.

The Navajo refer to the canyon's original occupants as Anasazi, which means "ancient ones" in the Navajo language, and also connotes ancient people from outside the tribe, according to Wilson Hunter, chief of interpretation for the National Park Service at Canyon de Chelly.

Other parks with similar ruins, like Mesa Verde National Park in Colorado, use the term Ancestral Puebloans instead of Anasazi.

Canyon de Chelly — pronounced SHAY — is also from the Navajo language. According to Hunter, "Chelly" is derived from a Navajo term, "tseyi," which means "within the rock."