Driving out of Aspen on the narrow, winding road that crosses central Colorado’s 12,000-foot Independence Pass, I’ve often turned off at The Grottos trailhead below the pass to explore this stretch of the Roaring Fork River. Much of the trail is covered with large, ancient slabs of granite and gneiss, on which glacial erratics of various sizes were scraped, shaped, smoothed, and deposited by ice flows that once traveled down the valley corridor toward Aspen.

Concealed among the rocks, spruce trees, and tumbling falls along the river, a carved-out realm lies within a sequestered cavern where the river once carved a sculpted corridor and hollowed a large chamber 30 feet deep. Skylights and rare shafts of sunlight leak through openings in its ceiling, illuminating walls tinted in warm hues by streaked erosion and stagnant organic sediment in its pool. The whole is lit by the reflected glow of cool-toned, high-altitude atmospheric light.

Littered with slowly rotting spruce logs, carried here by floods or fallen from the cave’s rim, they pile into a summer pool of snowmelt. During long winters, the cave is filled with a thick layer of ice, packed nearly to the top and sealing everything until the warmest months. On this day, now many years past, the cave evoked a contrasting mood: the somber quality of its light animated by the striking arrangement of its features – rock, light, wood, and water – that composed this picture.