Two backpackers, Johanie Garneau and Vanessa Louiset claim that during a recent tour of the vaults they photographed a strange blue mist in the shape of a skeletal face!
Here is the story from the Edinburgh Evening News:
Johanie and Vanessa joined two friends and around 20 others on a Mercat Tour of the vaults last Monday evening.
Johanie Garneau, 23, of Quebec, who is currently working as a waitress and living on London Road as she travels around the world, is convinced real ghosts haunt the vaults.
She said: "I know one of the tour guides, my friend Emma. So I went with my friends Eric and Vanessa and when we came to the first room underground I started taking pictures.
"Apparently, a tour guide saw a ghost in the same room about two years ago. He didn't mention it to the tour party straight away because he didn't want to frighten them. But then a girl actually fell to the floor when she felt something touch her and soon they were all screaming with fear.
"When we went on the tour, the guide had a candle and there were some lights on the wall so you could see where you were going a little bit. I was using the flash on my camera and Emma was complaining that I was blinding her.
"I took the flash off and took more pictures. Then when I checked the screen I thought, that's a ghost.
"I took it quite calmly because I've always believed in them.
"We got outside and in the clearer light it definitely looked like a ghost to us.
"I've always believed in ghosts even though this was the first one I've seen. I've travelled all over the world but this was the strangest thing I have seen so far."
Vanessa, from Normandy, France, who also lives in London Road, added: "I was really scared but Johanie was not so bad. I was convinced it was a ghost when I saw the picture."
Frances Mann, the product development manager at Mercat Tours, said out of the many pictures she is sent, photos showing mist were quite rare. She said that there are too many reports of strange happenings in the vaults for them all to be dismissed.
"A streak of light could be due to a camera shutter speed, but this is an interesting one, they are rather unusual to see," she added. "While there is an explanation for many, we do get some strange pictures.
"Sightings are getting more frequent. People are seeing more of Mr Boots, an intimidating figure, and Jack, a mischievous boy who throws stones."
However, Professor Richard Wiseman, a researcher into psychology and the paranormal, remains sceptical. He held an experiment in the Edinburgh vaults two years ago, during which volunteers spent the night there, with around half reporting "weird" experiences.
He said: "You can get these effects naturally. I would rather see what else could be causing them first, sometimes it is something very obvious."
? ONE of Edinburgh's scariest spots was the site of a ghostly experiment earlier this year.
Psychology and paranormal researcher Professor Richard Wiseman, right, was keen to find out why people report certain feelings or sightings in specific places.
He gathered 200 volunteers for tours of Mary King's Close under the Royal Mile during the city's Ghost Fest in May.
The experiment began with a series of tours around the darkened rooms and passages beneath the City Chambers, where unexplained paranormal activity has been reported since the 17th century.
Volunteers were led into some of the underground street's less well-known nooks and crannies and asked to note anything unusual they experienced. Each volunteer's journey was recorded by the scientists, enabling them to pinpoint exactly where someone was standing when they claim to have picked up on something spooky.
Reports of ghoulish experiences were then mapped with the sites where previous visitors had seen ghosts.