By Joan Melcher

Locals call it the original Stair-Master. And in fact, the zigzag path up Mount Sentinel on the edge of the University of Montana campus easily predates any gym gizmo. Its story starts in 1908 (some say 1909), when students cut, whitewashed, and arranged rocks to form an M.

The 13 switchbacks that rise 620 feet in just over a half a mile promise a vigorous workout. Arriving at the letter (now made of concrete), hikers enjoy a sweeping view of the campus (alive with ant-size students, faculty, and grazing deer), the Bitterroot Range in the south, the Rattlesnake Wilderness in the north, and Clark Fork River unfolding like a blue ribbon to the west.

As you make the climb, you may hear the university’s Main Hall clock chime the hour. Later, toast the trail’s birthday by buying an I HIKED THE "M" T-shirt at the campus bookstore.

A dash to the site and back takes half an hour, but allow an hour if you want to enjoy the views and catch your breath. The trail starts at Phyllis Washington Park off Campus Drive. For more alphabetical highs around the West, pick up the book Hillside Letters A to Z.