Mysterious tunnels or "secret passages" are a common element of the local folklore tradition in Europe. Such tunnels are said to physically link prominent places such as country houses, castles, churches, ancient monuments and other, often medieval, buildings.

Legends about the existence of secret tunnels usually involve improbably long subterranean passages, sometimes running under major obstacles such as rivers and lakes to reach their destinations. Religious buildings, monks and the landed gentry are particularly common elements in many tunnel stories.

It is unlikely that many of the recorded tunnels exist physically, for this is a characteristic of their very nature; their significance lies in the number of similar legends of tunnels that have arisen and in connection with the more esoteric notions of channels or paths of earth energy, and such.

The origins of secret passage myths

Underground structures have a fascination due to their being hidden from view and their contents, purpose, extent and destinations remaining unknown. Over the centuries many underground structures have been discovered by chance, ranging from Cornish fogous, souterrains that are possibly Pictish, Roman and medieval sewers to smuggling tunnels, escape tunnels, siege tunnels, and the like.

On occasion, possible tunnels prove to be of purely natural origin, such as at Cleeves Cove cave in Scotland, or Kents Cavern in England. The site at Cleeves Cove cave was previously known as the 'Elfhouse' or 'Elfhame',Paterson, James (1863-66). History of the Counties of Ayr and Wigton. V. - III - Cunninghame. J. Stillie. Edinburgh. p. 140. the locals at that time believing that elves had made it their abode.Dobie, James D. (ed Dobie, J.S.) (1876). Cunninghame, Topographized by Timothy Pont 1604–1608, with continuations and illustrative notices. Pub. John Tweed, Glasgow. P. 125.Ness, J. A. (1969 - 70). Landmarks of Kilwynnyng. Privately printed. p. 31.

Rarely, natural caves or tunnel systems can be of great extent; the cave system with the greatest total length of passage is Mammoth Cave (Kentucky, USA) at in length, whilst the next most extensive known cave is Jewel Cave near Custer, South Dakota, USA, at .

Some castles really did have escape tunnels, such as possibly the short passage located at Loudoun Castle in East Ayrshire, Scotland, which leads from the old kitchens to a 'tunnel-like' bridge over the Hag Burn; this may however have been a drain of some kind. Other examples were longer: the young king Edward III was imprisoned by Roger de Mortimer, 1st Earl of March at Nottingham Castle, and in 1330 a small group of armed supporters of Edward III made use of a long, winding secret passage which led directly into the castle, allowing them to surprise and capture Mortimer.

Other tunnels are products of an excessive desire for personal privacy, such as at Welbeck Abbey and Brownlow Castle. Another tunnel allowed for the supposed free and secret movement of monks, abbots and other ecclesiastics who may have had cause to keep a low profile for fear of attack or abusive treatment during periods of unrest or persecution. Smugglers at times avoided the excise man by making use of drains, sewers or water supply conduits, although in a few cases they seem to have constructed tunnels for the purpose of smuggling.

Bruce Walker, an expert on Scottish vernacular architecture, has suggested that the relatively numerous and usually long-ruined ice houses on country estates may have led to Scotland's many tunnel legends. The appearance of ice house entrance could have prompted the uninitiated to make such deductions since ice houses are often inconspicuously located in such places as ha-ha walls, house and stable basements, woodland banks, and open fields.Walker, Bruce (1978). Keeping it cool. Scottish Vernacular buildings Working Group. Edinburgh & Dundee. Pages 564-565

Many legends are associated with the actual and supposed activities of the Knights Templar and they are rich in stories about tunnels connecting the various properties that the order possessed up to the 12th century, when it was suppressed.

Sigmund Freud, Carl Jung and others had various psychological interpretations of the symbolic meanings of tunnels and these may have a part to play in the origins of tunnel myths.

Examples

Denmark

In the city of Aalborg, a tunnel is said to have run from the convent under the fjord to another convent near Sundby. This tunnel had branches which ran to an old bridge, two churches and to the castle of Aalborghus. A student once tried to explore the tunnels with a long cord, a sword and a light. The broken cord was retrieved, but the student was never seen again.

England At Furness Abbey a tunnel has been said to run underneath the Abbey to both Piel Castle and Dalton Castle. This was said to be how the monks travelled between each monument to receive foodstuffs and keep watch over the towns. It has also been rumoured that the Holy Grail and King John's missing jewels are hidden somewhere inside it.

Richmond Castle in North Yorkshire stands in a cliff-top position overlooking the River Swale. A potter named Thompson is said to have discovered a tunnel entrance at the bottom of this cliff. Following it deep into the hillside, he came to a large cavern where slept King Arthur and his knights around the famous Round Table. On the table lay an ancient horn and a mighty sword. Thompson reached out and picked up the horn, but the sleepers began to awake and, fearing for his life, the potter fled. As he raced down the tunnel back to daylight and safety, he heard a voice behind him declare:

"Potter Thompson, Potter Thompson! If thou hadst drawn the sword or blown the horn, Thou hadst been the luckiest man e'er was born."

The tunnel appears to have been well known, though the cave remains hidden. A second story tells how this subterranean passage is supposed to run from the Castle to nearby Easby Abbey. Some soldiers once sent a drummer-boy along it to test the theory and followed the sound of his drum almost halfway to the Abbey. The drumming suddenly stopped and the boy was never seen again, but his ghost is said to haunt the tunnel, from where a slow drumbeat is still sometimes heard. A memorial stone marks the spot at which the drum beat was last heard. It is believed that the legendary tunnel was constructed in medieval times as an escape route to the castle for the abbot and canons of the abbey in case of an attack from the Scots, who were continually making raids into the northern counties of England.

A smugglers' tunnel is said to run from Smugglers' Farm in Herstmonceux, Sussex to the Pevensey Marshes, a good distance away. A whole network of secret Knights Templar tunnels is said to run beneath Hertford Castle, running to Dinsley and other local places.

A 'secret tunnel' exists at Pevensey Castle in East Sussex, although not open for public access. It links the keep with the former market square and is thought to be Norman in origin; it was reused during the Second World War.

A series of tunnels are said to lie beneath Glastonbury Tor. The most famous tale is about a tunnel from Glastonbury Abbey to the Tor. At one time some thirty monks were rumoured to have entered the Tor via this tunnel, but only three came out again, and two of them were insane and one was struck dumb. Another widely believed legend is that of a long-distance tunnel leading from the crypt of the Lady (or Galilee) Chapel, under the River Brue to a distant point, possibly to the village of Street, where a passage exists from an outlying building in the grounds of the old manor house. A dog is said to have been put into the tunnel at Street and found his way out at the Glastonbury end.

A tunnel is said to run from King's College Chapel to Granchester Manor, Cambridge, passing under the river Cam.

A tunnel is said to run from Newbury Town Hall to St Nicolas Church. This belief may have started because there are east-west flowing brick Victorian service tunnels running from roughly the Newbury arcade towards this church; these were exposed to the public's gaze during construction work. A tunnel is also said to run from Newbury Castle (400 ft above sea level) and Shaw House (260 ft, thus 140 ft below it). The point of entry is said to be a hollow space (now blocked) in the south-east angle of the enclosure. In 1930 workmen investigated the legend by excavating the entrance, but found nothing.

At Necton in East Anglia a tunnel is said to run from the restored 14th-century church of All Saints to Necton Hall, in possession of the Mason family since the time of Henry VII.

The first of a number of legendary tunnels under Norwich leads from the Castle (TM232085) to the Guildhall (TM231085) near the market-place, erected 1407-13 on the site of the old tollhouse. It still has a 14th-century vault below it that was the crypt (and prison) of the former building. A second tunnel (in which a pig was once lost) heads from the Castle for Carrow Priory (TM242073 area), a Benedictine nunnery whose scant 12th century remains on the outskirts of Norwich are incorporated into a residence of the Colman family, near the junction of King Street and Bracondale. The third tunnel from the Castle ran to the Norman cathedral to the north-east (TM235089), begun in 1096 by Bishop Herbert de Losinga and finally consecrated in 1101-2. Yet another subterranean way links the Castle with the Crown Derby near the Guildhall.

At Norwich Cathedral another tunnel begins, running for about nine miles to the ruins of St Benet's Abbey (TG383157) on the marshes at Ludham. A much shorter one, allegedly used by monks, was said to run from the cathedral to Samson & Hercules House. The Anglia Restaurant in Prince's Street has a splendid groined crypt for a cellar, and two tunnels from here are said to lead to the cathedral and to St. Andrew's Hall. Monks supposedly used a tunnel from the cellars of the Shrub House at the corner of Charing Cross Street to the site of St. Benedict's Gates.

In early January 1644, Cromwell sent his forces to Norwich to demand the surrender of a small group of Royalists, whom he heard to be present at the Maid's Head Hotel. According to legend, as the Parliamentarians entered the hotel, the Royalists retreated through a secret tunnel, stretching steel ropes across the way behind them. Many of Cromwell's men (and their horses) were beheaded as they raced through the tunnel in pursuit, and this incident is used to explain the sound of ghostly hoofbeats often heard emanating from under the ground around the Cathedral Close.Atkin, Malcolm (1975), The Tunnels of Norwich, in 'Norfolk Fair', May 1975, pp. 6 - 7.

One smugglers' tunnel was rumoured to run from Kinson, now a Bournemouth suburb, to the coast some four miles away.

In the 19th century, it was said that an underground passage ran from the remains of the 12th century Gisborough Priory, immediately south of Guisborough parish church, to a field that lay in the parish of Tocketts. Halfway along was said to be a chest of gold guarded by a raven or crow.Henderson, William (1866). Notes on the Folk-lore of the Northern Counties. In Redcar and Cleveland almost every old castle and ruined monastery has its legend of a subterranean passage leading therefrom, which someone has penetrated to a certain distance, and has seen an iron chest, supposed to be full of gold, on which was perched a raven. The raven may suggest a Scandinavian origin of the legends.

Bracknell's Old Manor is a sturdy 17th century brick manor house having a priest hole and is said to have secret passages connecting to the exterior.

Droitwich Spa is said to have a passageway that leads from St Augustine's church, Dodderhill, to Friar Street in the town centre. A system of tunnels is said to run from there to St Augustine's and St Andrew's churches.