Secret subterranean shell grotto
Watching Country Tracks this morning, I was reminded of something from my childhood – Margate Shell Grotto.
Discovered in 1835 by a man and his son digging a duckpond, the grotto is 70ft of winding underground passages culminating in an oblong chamber all decorated with shell mosaic walls and ceilings – and the focal point of many a school trip. According to the website there are roughly 4.6 million shells covering 2000sqft of surface.
My favourite part of the grotto is that there is precisely zero known about its construction and intention. When on school visits we were always invited to write stories and draw pictures showing how and why we thought the grotto had come into existence. As you can probably imagine, these generally ranged from Power Ranger secret bases to mermaid dressing rooms rather than the more conventional Knights Templar conspiracy theories and secret cults.
Since abandoning my childhood mermaid conclusions I assumed that it was devised and created to be something personal and beautiful – something stunning, secret and selfish by someone with a lot of time and shells on their hands – but I think that says more about me than it does about the grotto. Current thinking and evidence positions it as a sun temple – you can read more about that on the official site.
When it was first opened to the public the shells were a variety of colours and textures but the gas lamps used early on to illuminate the tunnels covered everything in a silvery grey layer of soot. The soot has added to the mystery as it makes carbon dating ridiculously unreliable.
Apparently the mortar might be a better bet but English Heritage and the current owner are more concerned with keeping the whole thing from disintegrating at the moment. If they do ever get a complete analysis together it will be really interesting to see the results – the glue is fish based and contains volcanic elements, but also has ingredients that have never been identified.

Shell Grotto - reproduction of the star pattern to show original colours and impact - photo by rocketlass reproduced under Creative Commons licence

Shell Grotto - detail showing star pattern - photo by rocketlass reproduced under Creative Commons licence