Behind his looming figure an oak door leads down to the catacombs that stretch for 2km under the old part of Prague.

Since the city was founded almost 1500 years ago, it’s been the scene of intrigue, sorcery, torture, murder and general skulduggery. Many of the skulls that were ‘duggered’ are said to be lying in the darkest corners of the catacombs, while the tormented souls who once inhabited them fly up the cobbled streets and down the corridors of ancient buildings of what is known as Europe’s most haunted city.

“We can’t enter those terrifying tombs. For one thing we might not make it out alive,” our guide continues. “For another it is off-limits as an archaeological site.”

McGee is a Florida-born paranormal investigator who seems to spend an unhealthy amount of time lurking in the shadows and prowling the back alleys of Prague. He’s a walking encyclopaedia of the ghosts of the old city. His well-researched stories are further spiced by an imagination that might have been founded by spending too many of his formative years playing Dungeons & Dragons.

If all the stories are true, devils, phantoms, goblins, water-spirits, witches, giants and poltergeists almost outnumber tourists in old Prague. Even Charles Bridge, Prague’s most famous landmark, is said to have gold embedded in it as a deterrent to the city’s ghostly inhabitants (apparently they fear gold).

Headless ghosts in particular parade these streets by the score. Countless people lost their heads in Prague, but the most famous are probably the 27 Protestant lords who were beheaded in Staromestské Square for their habit of throwing Catholic envoys onto the castle dung heap. It’s said the headless lords are still seen from time to time and their apparition foretells bad timesfor Prague’s citizens.

“Where do you think you go when you die?” A finger points at my chest, but before I can start mumbling about insects, dust and grass, McGee expounds the scientific side of parapsychology. As a paranormal investigator, he’s driven by finding proof for the weird activity that seems to be going on around us at this very moment.

“Cameras behave strangely around here,” he says, glaring meaningfully at the Nikon around my neck. I shift it around my side — beyond the reach of whatever curse he might place on an otherwise promising magazine assignment — and avert my eyes to the bats swooping around the towers. “Anything could happen here,” I think. “This is Bat Country.”

“You can open your extrasensory perception but the naked eye cannot usually see psychic energy. Our cameras capture what is in front of them at 1/1000th of a second. They will show orbs — little balls of otherworldly energy. They will show vortexes — ripples of hairline energy that zip across the camera’s sensor.”

We stop before the carvings and statues on the Church of St James, apparently particularly known for the abundance of orbs that haunt the place.

When the first one is captured on camera I realise they look suspiciously like little spots of lens flare. With a few minutes practise I am able to not only shoot these orbs at will but actually to slot one between the rather more impressive orbs of a well-developed Czech lady who is too engrossed in McGee’s parapsychology to notice.

The citizens of Prague enjoy their ghost stories. Even the most confirmed sceptic would have to admit that once you have heard some of the gruesome stories that are part of Europe’s most haunted city you somehow tread more warily, with a renewed respect for things that can’t be explained.

“The people who built St Tyn’s church might have been staunch Christians,” McGee points out later, as we stare at the imposing carvings on the building’s shadowy portal, “yet, instead of angels and cherubs, they loaded the construction up with demons, dragons, gargoyles, hobgoblins and all man of hellish creatures.

“They weren’t taking any chances. And neither are we— we’re gettin’ outta here!