Royston Cave: The Strange Underground Mystery Beneath an Ordinary Street.
There are some places you visit because they are famous, and some places you visit because they sound strange enough that you cannot stop thinking about them.
Royston Cave is definitely the second kind.
From street level, Royston looks like a normal Hertfordshire town. Shops, traffic lights, pubs, people crossing the road, ordinary everyday life happening above ground. Then you go down a narrow staircase beneath the street and find yourself inside a man-made chalk cave covered in carvings of saints, symbols, figures, crosses and strange little faces that seem to stare back from the walls.
It is one of the most unusual places I have visited so far.
Beneath an ordinary street
One of the strangest things about Royston Cave is where it is.
It does not sit out in a field or hidden in woodland. It lies beneath the centre of Royston, under what now looks like an ordinary town junction. Above it are roads, shopfronts, traffic lights and people walking past with no idea what is underneath them.
Below that ordinary street is a chalk chamber full of carvings and unanswered questions.
The cave is man-made and cut into the chalk beneath Royston. It is shaped a bit like a beehive, with walls covered in carved figures and symbols. It does not feel natural. It feels deliberate. Someone made it. Someone shaped it. Someone carved into it.
The problem is that nobody knows exactly who, or why.
Why this spot matters
The location of Royston Cave is part of what makes it so interesting.
It sits beneath the meeting point of two ancient routes: Icknield Way and Ermine Street.
Icknield Way was an old trackway across southern England’s chalk landscape. Ermine Street was a Roman road running from London towards York. So long before modern Royston existed, this was already a place where people moved through, crossed paths, traded, stopped, prayed and travelled.
Royston’s name is also thought to come from Roisia’s Cross, a cross that once stood near the junction and was associated with Lady Roisia, a local noblewoman.
That makes the cave’s position feel important even before you get to the more mysterious theories.
When was Royston Cave discovered?
Royston Cave was rediscovered by accident in 1742.
A workman was digging in the town’s old butter market when he struck a buried millstone. Underneath it was a deep shaft leading down into the chalk.
In the very practical health-and-safety style of the 1700s, a small boy was reportedly sent down with a candle to see what was there.
People above were apparently hoping for treasure.
What they found was not treasure in the obvious sense, but it was far stranger: broken pottery, jewellery, human remains, and walls covered with carved figures.
The frustrating part is that there are no clear records of the cave before that discovery. No neat explanation. No handy medieval note saying, “This is what we built this for.”
That missing paper trail is one of the reasons Royston Cave still attracts so many theories.
What are the carvings?
The carvings are one of the main reasons the cave is so fascinating.
Some are linked to Christian stories and saints. There are carvings thought to show St Catherine, who is often shown with her breaking wheel, and St Lawrence, who was traditionally said to have been burned on a gridiron. There are also crosses, figures and scenes connected with Christian belief, suffering, punishment and devotion.
But the carvings are not all simple or easy to explain.
Some have been interpreted as pagan or fertility symbols, including a horse and a sheela-na-gig, which is a medieval fertility figure. There are also strange little human shapes, expressionless faces, figures holding objects, and symbols that are still debated.
That is what gives the cave such a strange feeling. It does not sit neatly in one category. It feels religious, symbolic, odd, personal and possibly layered over time.
Some carvings look serious. Some look almost childish. Some look like they belong in a medieval church. Others look like someone was down there trying to leave a message.
You are not just looking at carvings. You are looking at people from another time trying to say something, and we still do not fully know what.
The ley lines
Our guide also pointed out where the ley lines are said to cross above the cave.
I am keeping this carefully worded, because ley lines are not an established historical fact in the same way the chalk, carvings and discovery date are. They belong more to the folklore, spiritual and alternative-history side of the cave.
But they are absolutely part of the story people tell about Royston Cave.
The idea is that lines of energy or significance cross at or near Royston. The cave is often linked with the Michael Line, which is also associated with places such as Stonehenge and Avebury.
Whether you see ley lines as history, folklore, energy, or simply part of the stories people attach to strange places, it adds another layer to Royston Cave.
Standing above it at the road junction, it is odd to think that beneath the traffic lights, shopfronts and normal town life is a carved chalk chamber that people are still trying to explain.
The more solid historical point is the crossroads. Even without the ley line theory, Royston Cave sits under a place where people had been travelling, crossing paths, trading and stopping for centuries. That makes its location feel deliberate, even if its purpose is still unknown.
Who made Royston Cave?
This is where Royston Cave gets properly interesting.
There are several theories, but no definite answer.
Some theories connect the cave with the Knights Templar. Others suggest links with King James I or the Freemasons. There are also theories that it may have been used as a small private chapel, a quiet religious retreat, or even a place where one person lived apart from ordinary life for religious reasons.
It may also have had a more practical use, such as storage.
Nobody knows for sure.
The Knights Templar theory is probably the most famous one. It has obvious appeal. Royston Cave is underground, mysterious, full of religious carvings and located beneath an old crossroads. The Templars were active in Hertfordshire, and they had links to nearby places such as Baldock and Temple Dinsley.
But that does not prove they used the cave.
That is part of what makes the place so compelling. The theory is not completely random, but it is not settled fact either. It sits in that strange middle ground between history and possibility.
The cave refuses to sit still in one explanation.
Visiting Royston Cave
Royston Cave is open for guided tours from 4 April to 27 September 2026, on Saturdays, Sundays and Bank Holidays.
The tour times are:
Tour time
1.00 pm
1.45 pm
2.35 pm
3.20 pm
Ticket prices are:
Ticket
Price
Adult
£10
Concession, 65+ or student
£8
Child, 3 to 15
£4
Under 3
Free
The tour lasts about 40 minutes and cost me £10. For me, it was worth it.
It is not a huge attraction in the shiny, polished sense. It is small, underground and slightly awkward to photograph because of the lighting and the shape of the space.
But that is also the point.
You are not walking through a recreated visitor experience. You are standing inside a genuine historical puzzle.
The walls are chalk. The carvings are strange. The explanations are uncertain. The atmosphere is the best part.
I came out with more questions than answers, which is exactly what I want from a place like this.
Final thoughts
Royston Cave is not just interesting because it is old.
It is interesting because nobody can fully pin it down.
It might have been religious. It might have been secretive. It might have been practical and later became symbolic. It may have had several uses over time. The carvings might be medieval, but some could have been added later. The Templar and Freemason theories are fascinating, but not proven. The ley line stories add another layer, but belong more to folklore than firm history.
And yet, standing inside it, you can understand why people keep trying to explain it.
Some places give you facts.
Royston Cave gives you soft light, a wall full of strange figures, and a very good reason to keep looking.
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