Swarms of tourists gather at Artist Point on the South Rim to snap pictures of the deeply corrugated landscape. We derail to Uncle Tom's Trail to see the river plunge at Lower Falls. The scents of lodgepole pines and hemlocks suffuse the air and energize us as we descend 500 feet into the canyon. Sunlight illuminates a rainbow in the mist.

Viewing areas also punctuate the North Rim. Each overlook differs from the other in color, vegetation and mood. Inspiration Point and Grand View live up to their names. As we move down switchbacks on the Brink of the Lower Falls Trail, the sound of rushing water intensifies. At the trail's end, a railing prevents us from tipping right into the river where it suddenly drops 308 feet into a rock cauldron. It's definitely an "oh, wow!" moment.

Day Four

Going northward, we visit Tower Fall, a landmark made famous by painter Thomas Moran. His romantic depiction captured the imagination of Americans and bolstered support for creation of the national park. Before we veer to the east, we see two black bears digging for roots. Once we enter the Lamar River Valley, wildlife-watching reaches a higher level. Photographers equipped with long lenses set up camp at pullouts. They wait for mammals to emerge from thickly timbered mountains and show themselves in sweeping meadows. This is a prime habitat for grizzly bears, black bears, wolves, elk, bison, pronghorns and bighorn sheep.

We return to the Grand Loop Road and enter Roosevelt Country, a section favored by Theodore Roosevelt. Geological features include volcanic columns and a petrified forest, stemming from eruptions 50 million years ago.

The village at Mammoth Hot Springs is abuzz with people. It lies five miles south of the Gardiner, Mont., entrance to the park. Motorcoaches spit out scores of tourists of many nationalities. We hear a melange of accents at the visitors center in the 19th-century Fort Yellowstone district. The red-roofed stone buildings date to the time when the U.S. Army managed the park, before the creation of the National Park Service in 1916.

At Mammoth Hot Springs, mineral-laden hot water sculpts tiers of travertine (calcium carbonate). These formations differ from the silica-based geyserite deposits seen in other parts of the park. The stone terraces are ever-changing and otherworldly.

We leave the steaming, hissing springs area and ramble across grasslands behind the Mammoth Hot Springs Hotel. The Beaver Ponds Loop slips into a forest where limpid pools show the work of industrious beavers. Deftly skirting a black bear with two cubs, we descend through stands of aspens and enter Clematis Gulch. In the evening, from the porch of our frontier cabin, we see an elk silhouetted on a ridgetop.

Day Five