The Shell Grotto in Margate was Grade I listed on this day, 45 years ago

Photo Visit Thanet

On this day (February 22) in 1973  the Shell Grotto in Margate was given a Grade I Listing.

The Grotto was damaged during an air raid in the Second World War and it was this damage that prompted the first listing of buildings that were deemed to be of particular architectural merit by Historic England.

There are estimated to be less than 10,000 Grade I listed buildings in England and the Shell Grotto is probably one of the smallest!

Discovered in 1835, Margate’s Shell Grotto is 21 metres of winding passages decorated with 4.6 million shells. The walls are covered in images of gods and goddesses, trees of life and patterns of whelks, mussels and oysters. It terminates in a rectangular room, referred to as The Altar Chamber.

Photo Carole Adams

Some think it is an ancient Pagan grotto, others that it is simply an ornate Regency folly, although it lies under former farmland that was never part of an estate. Its true origins have never been discovered.

The most frequently used shells in the site are mussels, cockles, whelks, limpets, scallops and oysters. They are largely local. They could have been found in sufficient numbers from four possible bays: Walpole Bay in Cliftonville; Pegwell Bay, Cliffsend and Sandwich Bay.

The majority of the mosaic is formed from the flat winkle, which is used to create the background infill between the designs. This shell is rarely found locally so would have been collected from shores west of Southampton. There are also some exotic shells such as Queen Conchas from the Caribbean in the Altar Room.

Photo Carole Adams

The earliest reference to the discovery appears in an article in the Kentish Gazette of 22 May 1838, announcing its forthcoming opening as a public attraction. It has remained in private ownership ever since.

In 1932, the then new owner took over the Grotto, and soon afterwards substituted electric lighting for the gas lighting that, over the decades, had blackened the once-colourful shells. Cleaning trials show that in the majority of the Grotto the shells have lost their colour under the dirt and are white.

Photo Carole Adams

The structure has also suffered the effects of water penetration but was removed from the Buildings at Risk Register in 2012 after a five-year conservation programme, carried out in partnership with English Heritage. A scheme to sponsor replacement mosaic panels – The Roundel Project – was established in 2012.

The Friends of the Shell Grotto were formed in 2008 and are a not-for-profit trust established to promote, conserve, and preserve the Grotto as a unique historical monument.

Where is it

Grotto Hill, Margate

When is the Grotto open

Every day 10am to 5pm until October 29. Winter opening hours are weekends 11am to 4pm.


Adults £4, £3.50 concessions, £1.50 children aged 4-16. Family ticket for 2 adults, 2 children £8. Children under 3 get in free.


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