This may be the most famous horseback ride in the world—except you’ll be on a mule. An exhilarating trek that winds more than 5,000 feet down to the Colorado River at the Grand Canyon’s floor, this is also one of the most difficult to reserve. Unless you score a last-minute cancellation, expect to book at least one year in advance. And although approximately 3,600 people make the guided 20-mile round-trip ride on the Bright Angel Trail and back up on the South Kaibab Trail each year, groups are only 10 riders large.

You must, however, weigh 200 pounds or less, fully dressed. And yes, they do make you step on a scale. But if you need motivation to shed a few pounds, this spectacular ride is it.

Nothing compares to the drama of peeking into the Canyon’s nooks and crannies from the back of a mule. The many twists and turns of Bright Angel Trail intimately reveal its colors and majesty. The cliff-side trails high above the Colorado River and the breathtaking switchbacks of the Devil’s Corkscrew and “Jesus Corner” will make even the toughest old cowboy grab leather.

One memorable bend in the trail effectively looks straight over a 900-foot cliff, so leave your fear of heights at home. (The brochures do their best to warn those with any doubts.)

On my ride, I found the trail very safe and well maintained. It was about as wide as a sidewalk most of the way down, and though the trail is shared with hikers, the path is never crowded. Park rules give mules the right of way, and riding a big, sure-footed beast allowed me to breathe in the surroundings, instead of gasping for air—especially on the way back up the next day.

Teddy Roosevelt rode this trail 10 times and preserved the Grand Canyon as a National Monument in 1908. (It became a National Park in 1919.) You’ll also see ruins left behind by the ancient Anasazi. And, at day’s end, riders spend the night in cabins at the historic Phantom Ranch, built in 1922 along the Colorado River.

This ride was one of my peak Western experiences ever. It deserves a place on anyone’s bucket list.