Shell Grotto

Beneath an ordinary street in Margate, a narrow chalk passage leads down to rooms whose walls, arches and dome are covered entirely in shells — about 4.6 million of them, set into some 2,000 square feet of mosaic of stars, flowers, spirals and symbols no one has convincingly explained. Nobody knows who made the Shell Grotto, or when, or why.

The grotto was rediscovered around 1835; the earliest known account, from a newspaper of 1838, describes workmen at a cottage digging into an extensive underground space studded with shells. The layout is a serpentine passage about 70 feet long and 8 feet high, a circular rotunda with a shaft rising to daylight beneath a dome, and a rectangular chamber of roughly 15 by 20 feet, often called the altar chamber. The patterns are made mostly of mussels, cockles, whelks, limpets, scallops and oysters, set against a background of common periwinkles.

Theories about its origin range widely: an 18th- or 19th-century folly, a secret meeting place, even an ancient temple. A 2006 study for the Kent Archaeological Society suggested a more modest beginning, a medieval chalk pit or denehole later reworked and decorated in the 17th or 18th century. The grotto is a Grade I listed building and was taken off the Heritage at Risk Register in 2012 after conservation work.

Margate, on the north coast of Kent, became one of England's first seaside resorts in the 18th century, when Londoners came by boat down the Thames to bathe; the grotto sits in the old town a short walk from the sands.

Getting there

The grotto is in Margate, under 1 km from the town centre. The nearest airport is London Southend (SEN), about 52 km away in a straight line but across the Thames Estuary, so the road route is considerably longer. Margate has a railway station with services to London.