№ 01Underground · Kent, England
The Shell Grotto
A subterranean passage lined with 4.6 million shells — and nobody knows who built it, or why.
Photographs Alby (CC0) · No Swan So Fine (CC BY-SA 4.0) · Wikimedia Commons
In 1835 a Margate labourer digging in a field broke through into something impossible: a winding underground passage with every inch of wall and ceiling covered in shell mosaic — cockles, whelks, mussels and oysters, around 4.6 million of them — ending in a rectangular chamber the Victorians called the altar room.
Nearly two centuries of argument later, nobody has produced a document, a date or a designer. Theories run from Regency folly to smugglers' store to something far older. It is Grade I listed, quietly open to visitors, and the mystery is entirely intact.
The knowledge
- Getting there
- Grotto Hill, Margate — five minutes' walk from the Old Town; the entrance is an unassuming doorway on a residential street.
- Best time
- Any wet afternoon: it's all underground. Check opening days before travelling — roughly daily Easter to October, weekends in winter.
- Local tip
- Pair it with Margate's tidal pool and the Turner Contemporary to make a full day of it.
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