Alberta has a lot of caves. Some, like the Castleguard Cave, are deep, dark and hard to access. Some, like Rats Nest Cave, can be explored with guides. On other pages, we’ll look further into Kananaskis’ natural caves.
But one cave is anything but natural, anything but hard to access, and features a very creative chunk of Alberta history. It’s a man-made cave, was not in any guidebook until 2013, and we’ll just bet you have driven by it a dozen times without knowing it. It’s downright easy to visit — perhaps too easy.
We will merely précis the history. The talented and knowledgeable local Bow Valley writer and historian Rob Alexander wrote a wonderful piece back in the winter of 2009 in Highline Magazine with more detail, and it’s worth a read.
In short, in the late 1960’s (no one is sure exactly when, but it’s long before there was a Provincial Park here), the Rocky Mountain Vaults and Archives Company blasted a cave into the side of Mt. McGillvary above the TransCanada Highway at Lac Des Arcs. The intention was to make a commercial secure underground storage vault for precious records, a permit for which was issued in 1969. Some have claimed it might also have been for use as a bomb shelter, for it was indeed started during the Cold War, but that’s an urban legend. It’s not a bomb shelter, or a bunker, as this story from a 1970’s edition of Weekend Magazine shows (sourced from, and thanks to, Marko Stavric).
While everything inside it is long gone (including the “alarm controlled reinforced concrete door”), the cave itself is much unchanged from the 1970’s, when it was abandoned before it was finished. It features a tunnel big enough to drive a truck through, leading straight back about 150’ into the side of the mountain. There are two large 80’ x 25’ rooms that lead off the side of the main tunnel. And that’s it.
The plan was to build a network of tunnels and rooms, but despite getting a license to operate the facility in 1969, it was never used. This could be perhaps because there always seems to be water dripping from the roof – not a great place to store vital documents.
All the rock from drilling the tunnel is just piled up below the entrance. The only light in the tunnel comes in through the entrance. Back in the back, it is dark and clammy and silent save for the endless drips of water. Despite the entrance being right above the TransCanada Highway, you can’t hear vehicles. It’s pitch black in the side caverns; last time we were in there, we had two flashlights, and it was just barely enough to see. The floor is flat but rocky. The photo at the top of this story is looking out the entrance from about 50′ inside. For a complete tunnel plan and a bit more history, see Ben Gadd’s article here.
This is one of those “hides in plain sight” things. While the cave’s entrance is literally 300 m off the Trans Canada at Lac Des Arcs, the entrance is only visible from the westbound lanes of the highway for a moment or two way back at the west end of Bow Valley Provincial Park. Even then you need to know what you’re looking for. The photo shows the view back to the highway from the cave’s entrance.
Now, this “secret” cave isn’t really all that secret – at least not to certain locals. Despite being a protected space inside Bow Valley Wildland Provincial Park since 1998, there is tons of evidence of continued and on-going illegal camping inside the cave. The cave stinks of campfires. Last time we were in there, we counted at least 10 rings or ash piles. There was not one part of the tunnel that did not have a campfire ring within 5 m of it. In the ceiling were some remaining reinforcement metal rods, and one sticks out from the ceiling about 2 meters. On the end of it was a dead glow stick, held on with electrical tape, directly above a campfire ring. There were broken beer bottles in most every nook and cranny. Graffiti goons had, of course, splashed a tag or two here and there.
There was so much graffiti in and around the cave that in the fall of 2019, a group of volunteers working with Parks staff hauled a generator to the entrance, and spent an entire day grinding, scrubbing and washing it all off.
We understand from talking to Conservation Officers that it’s a popular spot for locals to party (some local kids tried to hold a 300 person rave in there in August 2012, but they were found out before it started. The rave moved in secret to Grotto Canyon with rather messy results). All of which is a giant disrespectful shame when it takes place in our Protected areas. We are aware proposals have been floated to close the cave’s entrance off with a steel gate for this exact reason. 
Perhaps the reason for the mess in the cave is how easy it is to access, even though it wasn’t mentioned in any guidebook prior to 2013. That anonymity is how it became known in those days as the “Secret Cave”. These days, it’s often called “The Heart Creek Bunker”, which is also incorrect. But call it what you want; it’s hard to miss, being just a 20 min walk west from the Heart Creek parking lot on the original cave access road.
While a visit can be worth it, carry several strong flashlights, and watch for broken glass and garbage wherever you step. Perhaps greater knowledge and visits will provide the cave the kind of protection and respect it really needs.
