The aspen trees' bright yellow leaves stood out among the dark green pines surrounding them. "Cool," I murmured to myself.

Then the sun slid out from behind the fluffy clouds and bang, it was like someone had thrown a light switch. The bright yellow leaves exploded into an almost blinding burst of glowing gold.

"Wow!" I said, almost shouting.

It wasn't the first - or last - time I used that word during almost two weeks traveling around Colorado last fall. That's the kind of place it is. Whether it's fall color time, winter, summer or spring, the wow moments keep stopping you in your tracks.

Check out these five ways to collect your own wow moments.

1. Mountain bike

Wow moment: The Lower Loop Trail heading out of Crested Butte is ranked "easy," as mountain bike trails out here go. But then you're flying down or struggling up one of its hilly sections on a 12- to 18-inch wide single-track trail, dodging rocks in the path, and you notice that the outer edge of the trail drops off nearly straight down, promising a nasty 20- to 30-foot plunge if you slip up. It's not the time to be rubbernecking. Save that for when you stop to catch your breath and marvel at the aspen- and pine-covered mountains rising around you.

Where: Crested Butte, sitting at nearly 9,000 feet in the very mountainous west-central part of the state northwest of Gunnison, is considered by many to be the country's best mountain-biking destination. Trails of all skill levels form a web around the tiny, picturesque onetime mining town. Just be sure to pack an extra set of lungs.

Information: www.visitcrestedbutte.com; Crested Butte Chamber of Commerce, 800-545-4505, www.crestedbuttechamber.com.

2. Kayak

Wow moment: Haviland Lake is not far off a busy highway, but sitting in a kayak out in this little gem, with pine trees decorating the shores and mountains nearly everywhere you look, I feel like I have my own little piece of wilderness. The water's cold but not frigid, as I walk my boat away from shore before slipping into it. And, it's a cliche, but it really is crystal clear. There's a campground here, but on a weekday in early October it's empty, and only a few fly fishermen quietly flog the water. A soft breeze; the glint of sun on the flat waters; puffy clouds on the robin's-egg-blue sky, and those mountains all around. It doesn't get much better than this.

Where: Haviland Lake is less than 20 miles north of Durango, off U.S. Highway 550, which stretches on up to Silverton and Ouray and is one of most spectacular drives around.

Information: U.S. Forest Service, www.fs.fed.us; Kayak Online, www.kayakonline.com/colorado.html.

3. Hike

Wow moment: Though the early October temps were warm and the day sunny, the shaded parts of the rocky trail up to Lake Haiyaha had their challenges thanks to a snowstorm earlier in the week whose remnants had turned to ice, inviting a spill for the careless hiker. The trail, moderately steep in spots, is a spur off the popular trail that goes from the 9,475-foot elevation Bear Lake Trailhead to Nymph, Dream and Emerald Lakes.

Where: The trail is in the east-central part of Rocky Mountain National Park, northwest of Denver. During the peak summer season, park officials recommend taking the shuttle bus to the Bear Lake Trailhead because of the trails' popularity and the limited parking.

Information: Rocky Mountain National Park, www.nps.gov/romo; Colorado Tourism, www.colorado.com.

4. Drive

Wow moment: I'm going to cast my vote for the Kebler Pass Road, an unpaved two-lane that heads west from Crested Butte. This road isn't a nail-biter like some, but for sheer beauty, it's spectacular, meandering through mile after mile of aspen groves.

Where: Kebler Pass Road goes up over the almost-10,000-foot pass to Colorado Highway 133.

More wows: The Million Dollar Highway - U.S. Highway 550 between Ouray and Silverton - might be named for the million-dollar views. Though I like to think it's because when you're driving it, you're going to wish you'd bought a million-dollar life insurance policy. If you're bothered the least little bit by heights but revel in sheer terror, this is your highway.

Information: Colorado Scenic Byways, www.coloradobyways.org; Colorado Department of Transportation road reports, www.cotrip.org.

5. Vintage train

Wow moment: When you're riding in an open rail car, you can hear that trains really do go clickety-clack as they scoot down the track. Also, on this train you occasionally inhale a big whiff of the coal smoke blowing back from the steam engine, and your eyes might tear up when a smidge of coal ash blows in. But who cares?

Where: Colorado may have more scenic trains than anywhere else in the country. Other lines, some vintage and some not, include the Pikes Peak Railway, the Royal Gorge Route Railroad, the Cumbres & Toltec Scenic Railroad, Georgetown Loop Railroad, the Ski Train, Leadville & Southern Railroad, Cripple Creek & Victor Narrow Gauge Railroad, Rio Grande Scenic Railway.