These Iron Age tunnels (called fogous) are one of England’s biggest mysteries that few bother to explore.

If one is interested in the mysterious underground world of urban tunnels, then London is one of the best places to sleuth.

London is full of abandoned military, civilian, postal, tube, and other tunnels – some are open for tours, some are open secrets, and some are speculation. But there’s more to England’s tunnels than those in London.

England boasts some of the oldest tunnels in the world dating back some 2,400 years (predating London). Ancient tunnels are fascinating and were often gre at feats of engineering. For thousands of years, the longest tunnels were those built by Emperor Claudius in the Roman Empire in Italy to drain a lake.

The Ancient Tunnels of Cornwall
Cornwall lies at the southwestern extreme of England (and is known as one of England’s favorite holiday destinations). In these charming lands of dramatic coastlines and rolling hills are over a dozen ancient tunnels.

A casual visitor is unlikely to know there are some of England’s most mysterious prehistoric surprises in this unassuming part of the country. These tunnels remain something of a mystery – no one seems to know why they were built.

“Obviously, all of this monument building did not take place at the same time. Man has been leaving his mark on the surface of the planet for thousands of years and each civilisation has had its own method of honouring their dead and/or their deities,” says the site Cornwall in Focus.

There are a total of fourteen known ancient tunnels in the region. They are known as “fogous” (from a Cornish word for cave). While there are similar “fogous” in Scotland, Ireland, Brittany, and Normandy, these are the only such tunnels known in England.

The fogous required considerable investment of time and resources “and no one knows why they would have done so,” says the BBC. It’s interesting to note that all 14 of the fogous have been found within the confines of prehistoric settlements.

The Mysteriousness of the Fogous of The United Kingdom
There are even older tunnels in the UK – like the labyrinthine copper mines that were tunneled around 3,800 years ago in what is today Wales. But what makes the “fogous” different is that they weren’t just dug out, they were also built.

It is thought that the ancients dug deep trenches and then built stone walls around them before topping them and capping filling in the area
Age Built: In The Iron Age
Halliggye Fogou is the best-preserved fogou, but it is also odd. It has an 8.4-meter passage at a height of 1.8 meters, but it narrows into another 4-meter long tunnel that’s just 0.75 meters tall. Another tunnel branches off to the left and extends 27 meters (3x longer than the main chamber).

Suggestions have included whether they were hiding spots, burial grounds, used for storage, places to commune with the gods, or ceremonial. But none of these explanations seem satisfactory and archeologists are still at a loss to explain the intensely odd design of the fogous.

Archeological digs have failed to validate any of these hypotheses. Of course, none of these are mutually exclusive, and they may have had multiple uses.

Purpose: The Purpose of The Fogous Remain A Mystery
All the fogous have been found within pre-historic settlements.

More Being Discovered and Visiting A Fogou
More may be hiding away as yet undiscovered. Another called Boden Fogou was found by a farmer when he was laying a pipe in his field in 1991 according to the BBC. Another was found by a tractor digging five years later.
“In other words, none of it seemed designed for easy access – a characteristic that’s as emblematic of fogous as it is perplexing,” wrote the BBC’s Amanda Ruggeri.

If one is visiting the other countries of the United Kingdom, check out the fogous or souterrains there. In Scotland, they are also oddly shaped but are in more of a banana shape (they are also found on the Isle of Skye). They curve around a roundhouse or in a cruciform.
Still others have speculated they were burial chambers.

An antiquarian who entered Halliggye in 1803 wrote that it had funerary urns. But others entered by the hole he made in the roof, and all the urns are gone. No bones or ashes have been discovered in the six tunnels that modern archaeologists have examined. No remnants of grains have been found, perhaps because the soil is acidic. No ingots from mining have been discovered.

This elimination of storage, mining or burial purposes has led some to speculate that they were perhaps ceremonial or religious structures where people worshiped gods.

If one would like to visit a fogou in Cornwall, the best-preserved one is Halliggye Fogou. It is managed by English Heritage and is open to the public.