No one knows who built it, or why, or when. Let’s explore the main theories behind Margate’s Shell Grotto.
In the seaside town of Margate in Kent, in a rather nondescript residential neighbourhood, is one of the most intriguing sights I’ve found anywhere in the UK: the Shell Grotto.
Before the 1830s, there’s no mention of the Shell Grotto anywhere. And then, entirely by chance when he was digging a duck pond, one James Newlove’s shovel broken through the ground into a cavern. Lowering his son into the cavern with a candle (health and safety be damned), it quickly became apparent that this was no ordinary cavern. No, this was something of a subterranean architectural marvel. Over 2,000 square feet of serpentine caves were more than 4.6 million shells, covering the walls and ceilings, arranged in mysterious patterns and mosaics.
By 1938, Newlove had opened the Grotto up to tourists and was charging entry. Since then, tourists have flocked to this underground wonder. But what exactly is it?
Nobody knows. We don’t know who made it, or why. Or when. According to Wikipedia, theories suggest the Grotto could have been built anytime in the last 3,000 years. A nice narrow timeframe, then.
This unknown has obviously added to the Shell Grotto’s legend and mystique – and also opened it up to any number of theories. Here I’ll look at a few of the most common.
What is Margate’s Shell Grotto? A look at the main theories…
Theory one: A rich man’s folly
Many people think that the most likely explanation for the Shell Grotto is that it was built by a rich man as a folly, likely in the 18th century. A folly was a building with no particular purpose, often made to look much older than they really are, or as a show of wealth. Follies were indeed popular at the time – and shell structures like this were, too. In fact, according to English Home around 200 shell grottos still exist in the UK. One can be found at Hampton Court, for example.
A couple of things work against this theory, though. Follies were a statement, a show of means and culture. But nobody knew that the Shell Grotto was there until it was found by accident in the 19th century. Why would somebody go through the effort of building it, and not tell anybody? And why would nobody remember it? To collect so many shells would surely have involved a great number of people. But when the Shell Grotto was discovered, it was a surprise to everybody.
Another thing working against this theory is the location of the Grotto. Follies of this type were usually built on a rich person’s estate. But as far as is known, the Grotto never formed part of somebody’s estate, and instead fell under farmland.
Theory two: Is the Shell Grotto an ancient temple?
So if it’s not an 18th century folly, could the Grotto be much, much older? Various theories exist around this – for example that the arrangements of the shells create some sort of prehistoric calendar. The idea that the Grotto is ancient is the coolest theory, of course. It captures the imagination to think of an ancient Thanet, an unknown civilisation working together to create this astonishing underground tapestry, traipsing down under firelight to worship their gods.
The designs of the mosaics have added to theories that the Grotto was built by an ancient civilisation. Many of them are quite abstract and have been described as similar to, for example, Ancient Egyptian designs. There’s also no overt Christian symbolism, which is certainly odd for a place with such spiritual undertones, in a country that has been Christian for over 1,000 years.
Patterns on the walls of the Shell Grotto
Could it have been the Romans?
One theory is that the Shell Grotto could have been a Mithraic Temple, from Roman times. Worshippers of the Roman cult of Mithras would use underground temples. The cult was popular in the 1st to 4th centuries AD, and was an early rival to Christianity. By the end of the 5th century AD, it had been suppressed, with Christianity the dominant religion. But during the Roman presence in Britain, which ended in the 5th century AD, it had a foothold. In 1954 for example, a Mithraic temple was discovered in the City of London.
In 2007, a domed cave was discovered in Rome, under the Palatine Hill, made in a similar style to the Shell Grotto. This adds a bit of weight to the theory that the Grotto could date from this era. On top of this, the cement which sticks the shells to the walls of the Grotto is also said to be similar to Roman cement, containing fish oil and crushed shells.
Another suggestion is that the Shell Grotto could have been created by the Phoenicians – an ancient seafaring civilisation from Carthage, who may have visited the country in the first millennium BCE.
Evidence that it’s not so ancient, after all
Sadly, there are a few things that suggest that the Grotto isn’t anywhere near this old. One of these is the shells themselves. Of the 4.6 million shells that make up the caves, almost all are native to the Kent coast. But a few are from much further afield. Queen conch shells in the Altar chamber originate from the Caribbean, which would have had to wash up on Thanet’s shore by chance or be brought from much further afield.
The arches in the Grotto also suggest a more modern origin, being in a Gothic style which was particularly popular in the 14th century. However, others have argued that this style of arch was used not for stylistic purposes, but just to reduce the risk of it collapsing.
Theory three: The Knights Templar
Perhaps the Grotto wasn’t created by an ancient civilisation, or by a rich 18th century landowner. Maybe it comes from the Middle Ages. One common theory is that it was built by the Knights Templar – a Christian military order with allegiance to the Pope.
Through extensive research, Mick Twyman of the Margate Historical Society found that on the arrival of each Spring equinox, sunlight enters the grotto through a dome with a circular opening. As the seasons change, the amount of light grows larger, shining lights over parts of the shells. At the arrival of the Summer solstice, the light seems to shine an egg like shape in the belly of a mosaic snake.
It’s a fascinating finding for sure. But the lack of obvious Christian symbols makes the idea that it was created by the Knights Templar questionable.
Theory four: A mixture of old and modern
A 2005 assessment by the Kent Underground Research Group suggested that the Shell Grotto could have originally been a denehole (a medieval chalk extraction pit) created many hundreds of years ago. The hole would then have been expanded (and decorated with shells) later, such as in the 17th or 18th centuries. Could this be the case – that the caves itself are much older, and the shells only added later?
Theory five: A smugglers cave
Another theory is that the Shell Grotto was used by smugglers, perhaps as a hideout. Smuggling was common in and around Margate. But this theory doesn’t hold much weight. The Grotto is quite far away from the sea, with no direct access to the water. And it doesn’t make sense that smugglers would decorate it with shells. This, at least, is one theory we can rule out.
Can’t they just carbon date the shells?
This was the main thing we wondered when we were visiting. Surely they can carbon date the shells, or the material used to stick it together? It seems this is mainly an issue of funding. To get an accurate carbon dating, the Grotto would need to provide a number of samples to mitigate against the more recent repair work that has taken place. And at the moment, their limited funds are focused on conservation.
Perhaps we’ll never know what the Shell Grotto is
There are many other theories, too – for example that the Shell Grotto was a meeting place for sea witchcraft where people would perform rituals and spells. But ultimately no one knows who created the Grotto, or why.
Whenever it comes from, and for whatever reason, the Shell Grotto is an astonishing achievement in the unlikeliest of places – the quintessential seaside town of Margate. Maybe we’ll never know why it was built, or by who. But maybe this only adds to its beautiful mystique.
You can visit the Shell Grotto in Margate, a short train ride from London. Read my guide to the town here.
Sources and further reading:
The Shell Grotto museum and official website
Exploring Kent’s Past, Kent County Council website
The Shell Grotto, Wikipedia
The Virtual Victorian, the Mysterious Shell Grotto
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