I soon discover there's a difference between hiking and hiking, a not-at-all subtle nuance that separates mindless stare-at-your-feet slogging from soul-soaring exploration and discovery. From our very first step, Walters gently directs us along the proper path. We stop regularly and often, gazing out at the canyon's sea of buttes and using our topographic maps and compasses to identify new features. On the upper ridges we inhale the scent of pine. We stand inside the cool entrances of abandoned mines, the silent rock, still flecked with copper tracings, testament to man's optimism and impermanence.

"There's a Zen saying: 'Be here now,'" says Walters. "If you are totally aware of your surroundings, of yourself, if you absorb everything, then you really appreciate the moment."

Best of all, Walters knows the perfect places in which to indulge this Zen joy. On our first afternoon, after setting up camp, we skirt the western edge of Horseshoe Mesa, following a barely discernible trail to a cave formed roughly 300 million years earlier. Squeezing through the narrow opening, we find ourselves in a living-room-size cavern.

That's only the beginning. Dissolved by water over eons, the porous limestone has become a series of squeezes and caverns running virtually straight shot back into the mesa.