Detours: Natural high

Estes Park, a two-hour drive north of Denver, is a town where the majesty of the Rockies collides with the culture of miniature golf. But most people who make it to Estes go for the Rockies. Or, more specifically, they go to drive the Trail Ridge Road.

Beginning just outside Estes and ending at Grand Lake, the 77km road traverses Rocky Mountain National Park. Also known as Route 34, it has been inspiring superlatives since 1932. Among other things, it's the highest paved road in the US. Seventeen kilometres of the road are above the tree line and 12km are above 3,350 metres. At its highest, the road reaches 3,713 metres above sea level.

The show - and it's just that, one glorious vista after another - begins at West Horseshoe Park, an expansive mountain meadow bounded by rust-coloured pines and home to bighorn sheep. Next is Many Parks Curve, a lookout where cameras never seem to leave faces. Here the view is of huge, forested moraines, more mountain meadows and the 4,346-metre Longs Peak. The mountain's friendly profile masks the steadily mounting toll of hikers and mountaineers who perish on its icy slopes.

It's hard to pull away from any of the views, but you soon realise there are always more to come. By Rainbow Curve, at 3,300 metres, the forest has thinned and only the hardiest trees remain. Clutching at the mountainside, petrified by the 160km/h winds that whip the slopes in winter, these stunted testaments to nature's tenacity have been shorn of all but their downwind branches.

But on Trail Ridge Road nature isn't the only supplier of spectacles. Equally captivating are fellow road users. From a group of hirsute Christian bikers to 10-metre recreational vehicles and a purring white stretch limousine, we're accompanied by every imaginable slice of mechanised America.

We pass a mountain biker resting and sweating beside one of the six-metre poles that in winter snows mark the edges of the road. Sometimes even these are buried. It can take the park service 40 days to clear the road at winter's end.

Another set of curves, more altitude, and the next display is Forest Canyon. Green slopes tumble into a valley thousands of metres below, where Big Thompson River begins its journey. On the other side of the valley spreads a panorama of 3,650-metre peaks, snow-packed couloirs and glacial lakes. Above us, the sky has taken on a malevolent hue. Moments later we hit the summit and begin the roll down towards Grand Lake.

But we don't make it that far. The predicted afternoon storms arrive and, having crossed the continental divide - the line separating the watersheds of the Pacific and Atlantic oceans - we turn back.

We stop at Fall River Pass at the head of Fall River Valley. A crescent-shaped bank of snow more than a metre thick continues to defy the summer sun. Hundreds of metres below, a small herd of elk frolics on the edge of a snow field. To the east, a series of towering peaks pricks the clearing sky. A woman whose twang suggests the south turns to her friends and says: 'Now tell me that the Big Bang did this.'

Trail Ridge Road is open, weather permitting, from May to October. Estes Park, on Route 36, can be reached from Denver via Colorado and Lyons