Check out this gut-wrenching clip from this past June -- just now surfacing -- of what appears to be a group of tourists visiting Russia's Sulak Canyon near Dagestan ... the bottom of which lies a little more than a mile below where these folks were to get a view right before things drop off ... thousands of feet up high.

For some reason, it looks like someone installed a swing set right on the ledge -- where people can get on the bench and be pushed over into the canyon side for a thrill/better view of what's below. Sounds neat in theory ... that is, until you see what happened next.

The two ladies plop down into the seat -- which looks to be connected to the swing set by a couple chains -- and then a man starts to give them a few pushes to catch momentum ... and catapult further and further over the edge. All seems to be going okay, at first, until their last swing forward.

Suddenly, one of the chains snaps, and the two women literally get flung from the seat and fall over ... and down. It's absolutely terrifying -- and you can tell as much by how people reacted around them. The video cuts out shortly after that, but there's a happy ending.

Reports say there was a wooden platform just beneath the ledge here -- good thinking on whoever put it there -- and that these women landed safely on that not too far down below ... suffering minor injuries and being able to be successfully rescued by family members.