One of the last places that someone might expect to encounter a ghost is atop a mountain, but there are a few sites where witnesses actually say that just such a spooky scenario unfolded.
YouTube user Dark5 has put together a chilling collection of hair-raising encounters with mysterious apparitions or entities on mountains both famous and infamous.
One of the most legendary tales featured in the video came from British mountaineer J. Norman Collie recounting his journey to the top of Scotland's Ben Macdui mountain.
According to Collie, as he was ascending the mountain, he suddenly heard the ominous sound of someone or something walking behind him.
The unexplained stalking, Collie said, left him "seized with terror," although he never saw what it was that was following him.
Subsequent visitors to Ben Macdui reported similar experiences and all of them noted that the eerie sounds also left them with a similar sense of overwhelming.
And some climbers who allegedly encountered what has become known as the 'Big Gray Man' claim to have caught a glimpse of the entity behind the footsteps and said that it resembled a ten-foot tall, gray humanoid.
Beyond creatures or beings purportedly making their homes on mountains, there are also a number of unsettling stories of ghostly activity seemingly centered around people who died during their ascent.
Following his record-breaking climb of Mount Everest in 2004, Pemba Dorje credited ghosts on the mountain with helping him achieve his accomplishment.
In what may have helped Dorje climb as quickly as possible, he claims that, during his ascent, shadowy black entities approached him with their hands outstretched and begging for food.
Could these have been the distressed spirits of the 300 or so climbers who have died en route to the mountaintop of merely hallucinations from Dorje as he ascended at a record pace?
Other spine-tingling tales included in the collection are an entity known as 'Spearfinger' that legend says lurks in the Smoky Mountains as well as mysterious, out-of-place radio signals received by climbers in the Himalayas that appeared to have been messages from mountaineers that were lost at the location in years past.