The six-mile canyon drive ends at a formation known as Temple of Sinawava, where the canyon begins narrowing to a slot only 30 to 40 feet wide.

The canyon used to be overwhelmed by traffic during the spring and summer, bringing noise, pollution and endless frustration for visitors who could find nowhere to park. The National Park Service responded by beginning a mandatory shuttle bus system in the year 2000.

During the summer months — April through October — the heart of the Zion Canyon is closed to private vehicles. Visitors board free propane-powered shuttle buses near the entrance station to complete their journey into the park.

While shuttle buses may rankle some who like the freedom of coming and going at will, the Zion system has proved a success. The buses run every six minutes during the day, stopping at all popular trailheads in the canyon, so people spend far less time waiting for buses than they did in the often-hopeless search for a parking space in the days before the buses. The buses also restored quiet to the inner canyon.

A separate shuttle bus route runs through the town of Springdale, at the park's main gate. Visitors dropped at the entrance by a city shuttle need only cross a foot bridge over the Virgin River into the park, show or buy their park pass, then re-board a park shuttle at the adjacent visitors center.

Two campgrounds are located just inside the park entrance, and a grocery store is located on the city side of the foot bridge. That means it's possible to spend a week or more at Zion — hiking all the major trails inside the park and using all the amenities in town — and never have to move your car from your campsite or motel.

Our stay was limited to only a few days, so we could not hit all of Zion's trails. But one we could not resist was one of its classics — Angels Landing.

Angels Landing is only a five-mile hike, but guides recommend allowing at least five hours because of the terrain the trail covers — a 1,500-foot climb through a slot canyon and out to a 5,785-foot peak perched at the end of a narrow rock fin. The name came from an early Zion explorer who looked up at the precipice from the canyon floor and declared "only an angel could land on it!"

This is not a hike for those afraid of heights. After a two-mile gradual approach, then climbing through a cool side canyon, the trail ascends Walter's Wiggles, a series of 21 switchbacks that steeply ascend a cliff wall, topping out at a broad sandy area known as Scout Lookout.