There's nothing more eerie than being cutoff from the world below the ground, surrounded by darkness with the constant sound of dripping all around you.
Underground spaces, whether manmade or natural, are cold dark and oppressive places. They're often hard to navigate due to their labyrinth-like passageway, making visitors feel lots and disorientated.
Many have a history of witchcraft, murder, death and wartime secrets, so it's no surprise that so many people report strange and paranormal occurrences in these types of locations.
Whether these phenomena are real examples of paranormal, or are just in the mind, there's no denying subterranean places are scary. So with that in mind, let's take a look at the ten most haunted caves, bunkers, tunnel networks and other manmade underground structures hidden beneath the ground all over the UK.
Today Chislehurst Caves are a tourist attraction and although they are called caves, they are entirely manmade. The intersecting tunnels cover a total distance of 22 miles and there's said to be paranormal activity on every turn.
Despite an unsuccessful exorcism, the strange goings on continue. Most of the reports involve claims of poltergeist activity, including rocks and chalk being thrown at visitors.
The famous show caves are said to be haunted due to their colourful past, most famously its former, a resident witch.
She is said to have cursed a monk from nearby Glastonbury, he came to the caves in search of the witch in an attempt to break the curse. He splashed holy water on the cave walls, which is believed to have turned into the impressive stalagmites visitors can see in the caves today.
Hack Green was first used during the Second World War, its purpose was to confuse German bombers looking for the vital railway junction at Crewe. In the 1950s, the site became part of the ROTOR project and a reinforced concrete bunker was built and became known as RAF Hack Green. After being abandoned for some years, the Home Office took it over and converted the bunker to Regional Government Headquarters which remained in use until 1992.
The bunker is now a museum, and guests and staff have reported paranormal activity, including seeing the apparition of a young woman in the bunker's former telecommunications area. An aggressive male spirit is also said to haunt this area.
In the main corridor witnesses have seen a man dressed in period uniform, or have picked up on a general feeling of unease. Part of the bunker is now a theatre, and here guests have reported being touched and even pushed by an unseen force.
The London Tombs are part of The London Bridge Experience, a tourist attraction on Tooley Street, in vaults below the southern end of London Bridge, built on the site of what was once a plague pit. As well as being a popular tourist spot, it's also a popular location for ghost hunts and is said to be the most haunted bridge in the world.
Staff and visitors have reported paranormal activity ranging from unexplained sounds like knocks, bangs and dragging sounds, through to poltergeist activity in the form of objects being thrown by an unseen force. There's even been reports of dark shadowy figures moving around in the creepy subterranean tunnels.
There's also been reports of a little girl who's believed to be called Emily. Other visitors have reported encountering an unenthusiastic staff member in the tombs. She's said to be dressed in character but doesn't interact with the guests, she simply stares at them. When the guests mentioned this to staff they are surprised to hear that there is no such woman working in that part of the tour.
The tombs were built over a plague pit and many think this could be the cause of the hauntings. The pit, which was discovered in 2007, contains a large number of skeletons that date back to the 11th century through to 17th century.
The bridge also has a grim past as severed heads were at one time displayed on the bridge after executions. This was commonplace in Tudor times when they used to impale the heads of traitors and criminals on spikes along the bridge.
The 1950s nuclear bunker is spread over three floors and is accessible through a 100 meter long access tunnel from an ordinary looking cottage, on closer inspection it's clear the cottage is far from normal, built with thick concrete walls and windows protected by steel shutters.
Visitors to the bunker, which is now a museum, have reported experiencing poltergeist activity, hearing growls and footsteps coming from empty rooms, and even witnessed full apparitions.
During the bunkers construction under order of the Air Ministry in the 1950s, crews are said to have disturbed an ancient burial ground. A foreman also died during the works. His hard hat was found floating in wet concrete, it's thought he was buried alive in the bunker's three meter thick walls. There's also said to be the ghost of a construction worker who committed suicide in the main stairwell.
Records show that a settlement has existed on the site of Dover Castle since Saxon times, it has a history of involvement in pirates, Napoleonic battles, and even housed a secret underground command centre in the Second World War.
The battlements are said to be haunted by a the ghost of a headless drummer boy who's believed to have been decapitated when he was attacked for the riches he was carrying while on an errand for his master. The castle is also said to be the home of a woman in red who has been spotted around the castle, as well as a cavalier.
The castle has a haunted underground area too. Below ground in the WWII tunnels, the ghost of many soldiers have been seen and their presence felt. Visitors have reported hearing disembodied voices, loud screams, and doors slamming, as well as experiencing sudden drops in temperature.
Advertisement ‐ Content Continues Below.
The Hellfire Caves are a manmade network of chalk mines, which extend a quarter of a mile underground near the village of West Wycombe. The caves have a past of satanic rituals, worship and sacrifice, making them a terrifying place to visit today.
The Hellfire Caves are said to have many resident spooks, including the spirit of Benjamin Franklin, who was a regular visitor to the caves in the 18th century. Another apparition regularly spotted is that of Paul Whitehead, a former steward of the notorious Hellfire Club from which the caves take their name.
There's also the spirit of a young girl called Suki, she's said to have been tricked into meeting a man at the caves, the visit resulted in her murder.
Nestle deep beneath the Royal Mile in Edinburgh there's a hidden a labyrinth of narrow streets and houses. The area of Mary King's Close was originally a number of streets lined with houses, taverns and shops. Buildings were up to seven storeys high and housed hundreds of Edinburgh's inhabitants, but in 1645 the city was hit by the bubonic plague and the confines of the close proved to be a fertile breeding ground for the black death.
In an attempt to stem the spread of this ravaging disease, city officials quarantined Mary King's Close, and although victims of the plague were cared for, many died in their homes.
By the mid 18th century, the council decided to build the Royal Exchange on top of the close. Residents left the area and the street became a subterranean underworld, buried for centuries, but the close was recently reopened, allowing its macabre history to be retold.
The close is said to be the site of dark shadows, strange noises and even apparitions of body parts have been reported here. Chesney's House, is said to be so scary, that some staff member refuse to enter certain areas on their own and the ghost of a man has been seen here before vanishing.
A building known as the "Murder House" is said to be the location of a killing. A woman murdered her son in law here and was executed for her crime. Since then his wounded figure has been seen and heard reenacting the moment of his death.
Annie's Room are said to be the most haunted part of the close, as well as cold spots, phantom voices and dark shadows, the spirit of a little girl has been seen wandering endlessly, trying to find her mother, who apparently left her to die during the plague. She's been seen so many times that guests often leave her toys to play with.
The tunnels were originally excavated to house the Drakelow Underground Dispersal Factory where Rover produced aircraft parts for the Air Ministry, after the Second World War it was refitted and put on standby during the Cold War as a bunker for the local government.
According to newspaper reports at the time, at least three men were killed by a roof fall while digging out the tunnels in the 1940s, there are reports since of factory workers being killed underground after being hit by trucks and while riding conveyor belts.
Modern-day visitors who dare to wander through the darkness have reported hearing strange noises, screaming and cries, and disembodied voices.
The tunnels are believed to have been built under an ancient hill fort which had its own graveyard where hundreds of bodies were buried. During the tunnelling the dead were disturbed and as a result a "demon guardian" of the burial ground is said to take a disliking to anyone who enters the tunnels.
This could account for sightings of a dark shadowy figure which has been seen by visitors. Airsoft participants have pursued fellow players in the darkness, only to turn a corner and find themselves faced with a dead end and no figure anywhere to be seen.
The Edinburgh Vaults are a network of eerie chambers which are formed in the arches of the South Bridge in Edinburgh. Due to the city's growing population, the 120 rooms or 'vaults' beneath the bridge were put to use to house taverns, workshops for cobblers and other tradesmen in 1788.
The vaults were damp with poor air quality and condition were grim, which resulted in businesses leaving. This meant that the dank caverns were overtaken by Edinburgh's poorest citizens, the homeless and criminals, who carried out activities such as illegal gambling, whisky distillery and even bodysnatching.
Eventually the vaults were filled in and forgotten about, until they were rediscovered in the 1980s and eventually opened as a tourist attraction. Thanks to its depressing past, the vaults are now said to be one of the most haunted places in the UK.
Visitors report hearing disembodied voices, including the sound of children crying. The mysterious sound of feet shuffling can also be heard coming from dark corners of the vaults, and people have reported being touched. During 'Most Haunted's' investigation of the location in 2008, one of their team was scratched by an unseen force, to this day it is still one of the team's most violent investigations.