Nestled along the scenic coastline of Thanet, on the far eastern tip of Kent, England, is the historic seaside town of Margate. Such is the breathtaking scenery here that the town has a long history as a seaside tourist resort, with visitors coming here since the 1800s to enjoy the beaches, the seaside caves, and the town’s famous “bathing machines,” and in the 1900s the Dreamland Amusement Park was opened, sporting the second oldest roller coaster in the world, opened to the public in 1920. Yet for years underneath the throngs of sea loving tourists there lurked a secret here, and no one was aware that beneath their feet was a mysterious sprawling complex made almost entirely of shells, which has remained an enigmatic location that has eluded understanding all the way to the present.

In 1835, a local farmer named James Newlove and his son, Joshua, were working on digging a new duck pond when they made quite a curious accidental find. At one point they broke through the ground to reveal an opening to the deep dark unknown below, an entrance into some mysterious underground realm. After fetching a light source, Joshua was lowered down into the opening to find that it was in fact a cave, but this was no ordinary cave. There in the flickering light of the torch were millions upon millions of shells arranged in ornate designs and images, completely coating the walls all the way down the passages that led into the gloom past the reach of the light.

The strange cave was found to cover a total area of around 2,000 square feet, consisting of winding undergrounds, small rooms, and an arched ceiling and entryways, all covered in approximately 4.6 million shells of various types including mussels, cockles, whelks, limpets, scallops, flat winkle, and oysters , all meticulously embedded into the walls and ceiling to form elaborate mosaics and geometric designs. These shells are arranged in intricate patterns and even representations of plants, animals, and humans, as well as what seem to be pagan imagery, and the whole thing seems to resemble Egyptian or Indian designs.

Through the mosaics runs a clear horizontal line, its purpose unknown, and at the end of the main passageway lies a chamber measuring around 15 by 20 ft (5 by 6 m) in area and with a domed ceiling, which contains a mysterious altar covered in more shells arranged into a likeness of the sun and the moon, as well as an opening to the outside measuring around 2 feet wide, which had previously been hidden but which now allows rays of light to pierce into the murk. It has been found in later years that during the Summer Solstice the sun shines into the room and the light can be reflected to directly hit the altar. Why? Who knows?

The whole of this magnificent grotto is an amazing display of art and painstaking detail, and it boggles the mind to think of how much time and effort it would have taken to dig out these passages and rooms and to precisely place each of those millions upon millions of shells. This would have been a major feat to not only secure and transport all of those shells, but to then make the subterranean complex and arrange them all, and experts have theorized that it likely took several generations to complete. Making it even more mysterious still is that no one is really sure of who made it or why, with many theories that run a range of possibilities. Some of the ideas that have been tossed around are that it was a place for pagan rituals, an ancient observatory or religious site, an astronomical calendar, a secret meeting place for some secret society such as the Knights Templar or Freemasonry, a pirate lair, or simply some rich eccentric’s hobby or even a hoax.

Making its origins more difficult to ascertain is the fact that we don’t even know how old it is. Shortly after its discovery, Newlove opened it to the public, and at the time oil lamps were used to illuminate it. This unfortunately created a sooty residue upon the shells which, besides staining them from their original white to a brownish hue, left a chemical film over them that has made it impossible to reliably date them. Because of this, we don’t know if it was created hundreds of years ago or thousands, further making its history elusive and enigmatic. In recent years the Shell Grotto of Margate had electrical lighting and still provides endless wonder for visitors, complete with an attached museum and gift shop, but its mysteries remain, and perhaps always will.