THE BIG PICTURES: CANYON DE CHELLY

An alcove in the sheer sandstone wall of Canyon de Chelly protects White House Ruins, an Ancestral Puebloan dwelling last occupied around A.D. 1275. A 2.5-mile (round-trip) trail from White House Overlook leads to the ruins and is the only way visitors may descend into the canyon without a permit or a Navajo guide. Shane McDermott

Cottonwoods at the bottom of Canyon de Chelly display their early-autumn hues near sunset. This view is looking northwest from Sliding House Overlook, one of several vantage points on the canyon's south rim; to the left is Spring Canyon, one of the main canyon's tributaries. Michael Wilson

LEFT: Early November brings the colors of fall to cottonwoods on the canyon's floor. A 2005 study documented nearly 800 plant species at Canyon de Chelly National Monument. Phillip Noll ABOVE: Mummy Cave Ruins, which has nearly 70 rooms, is the largest Ancestral Puebloan ruin at the monument. It's located in Canyon del Muerto, the main tributary of Canyon de Chelly. Derek von Briesen

Canyon de Chelly's best-known natural feature is Spider Rock, which rises more than 700 feet from the canyon's floor at its junction with Monument Canyon. It's named for Spider Woman, a key figure in Navajo lore. Tim Fitzharris

The yellows and oranges of fall cottonwoods contrast with Canyon de Chelly's red sandstone walls. The monument is open year-round, but monument officials say spring, summer and fall are the best seasons to visit. Dean Hueber