Discovered by William Henry Hubbard, his brother Charles and Griffith Jones during an 1893 hunting and prospecting expedition, Hubbard’s is a splendid solutional cavern on the south rim of Glenwood Canyon. Overlooking the Shoshone Power Plant and Interstate Highway 70, Hubbard’s Cave contains 1.2 miles of surveyed passageways.

In Glenwood Springs many years ago, I visited one of the Hubbards to find out more about his family’s namesake cave. Welcoming me into his home, he reported he knew the Mystery Pit from boyhood explorations five decades earlier. With friends, they tossed rocks into the shaft to hear them “bang and clunk” for several minutes. Curious as to the pit’s depth, one brave boy offered to be lowered on a rope to see if he could reach the bottom. Lantern in hand, he dropped out of sight into the gloomy depths. Unfortunately, the rope soon played out and he was pulled back up without solving the mystery. Allegedly 1,400 feet deep, the Mystery Pit once was a popular attraction, and visitors took the opportunity to toss rocks into it. By 1951, when National Speleological Society cavers first visited Hubbard’s Cave at the invitation of the city of Glenwood Springs, the pit had become hopelessly blocked with rocks and debris.

But here I was, leaning out over the fissure, hoping to catch a glimpse of its depth and better understand its mystery. About 15 feet down, I could see the dirt and rock plug appearing very much out of place. To my left, I noticed a steeply ascending tube – the Devil’s Slide – that probably was the source for much of the rubble.

Could this pit be 1,400 feet deep? Almost certainly not – 1,400 feet would put its base lower than the Colorado River! Quite possibly, however, the pit might extend to the base of the Leadville Limestone, which in this part of Glenwood Canyon was a hundred feet or more below the lip of the pit. Such depths are not unheard of in Colorado caves, which generally are horizontal in nature. Those caves with some depth, such as nearby Glenwood Caverns, do so by following a dipping rock stratum.

Glenwood Caverns is an exceptional choice for an initial visit underground in Colorado. Though it has 278 feet of known vertical development, improvements to the two commercially developed portions of the cave make it easy for underground enthusiasts to tour its corridors with only a little exertion.

Initially shown to the public by capitalist Charles W. Darrow in 1896, the cave was fully developed in 1999 by Steve and Jeanne Beckley. Incorporating the former Fairy Cave tour route shown from 1896 to the start of World War I, today’s tour also includes the spectacular lower cave, discovered in the late 1950s. Stairways descend through the spacious Barn to King’s Row, one of the most exquisite of Colorado’s known cave passageways. Filled with colorful stalactites, stalagmites and flowstone, King’s Row is a satisfying highlight of the tour. It also is the lowest point on the route, requiring visitors to ascend the stairways of the Barn back to the surface.

For the more energetic visitor, guided trips into an undeveloped region of the upper cave are available. Requiring visitors to squeeze and crawl through narrow and low tubes first explored in the early 1950s, several interesting and memorable chambers are visited, such as The Canyon, with its Bright Angel Trail and North Rim. Visitors also see the Pendant Room, the first big discovery of 1950s, and the Drum Room, where a false floor provides outstanding resonance for drumming. Visitors dirty and tired by their subterranean crawling will welcome the nearby Iron Mountain Station, where the Exclamation Point restaurant offers food and views of Glenwood Springs. The modern Iron Mountain Tramway provides all season access to the Station and to Glenwood Caverns.