Shell Grotto

The earliest printed account of the Shell Grotto appeared on May 12, 1838, under the headline "Extraordinary Discovery." Belle Vue Cottage, it said, had "been lately purchased by a gentleman" who had workmen "excavate some few feet." The work "was impeded by a large stone," and a "minute examination" found "an extensive grotto, completely studded with shells in curious devices." The proprietor intended "shortly to open the whole for exhibition, at a small charge for admission." The Grotto's own pages name the paper as the Kentish Mercury in one place and the Kentish Gazette in another.

The gentleman was James Newlove, who ran a boys' school called Dane House Academy down the road. By the Grotto's research, he began renting Belle Vue Cottage in January 1835 and installed his wife, Arabella, as head of a girls' school there. He bought the cottage and its land in August 1837, and the deed does not mention a grotto. Paying visitors went down on Monday, June 4, 1838, according to the Grotto. A 2005 paper published by the Kent Archaeological Society gives 1837. The cottage stands at the bottom of Grotto Hill as a private house called Rose Lodge, and Dane House Academy is now the Mulberry Tree pub on Dane Road.

Five versions of the find

The witnesses were interviewed decades later, mostly in the 1890s by Algernon Goddard, a later owner of the Grotto. They do not agree.

Frances Newlove, the schoolmaster's youngest daughter, was about 12 in 1835 and about 70 when Goddard interviewed her in 1893. She said her brother Joshua, then 16, "found the chalk loose at one end of the passage" and crawled in, and that she and "two or three other young girls" followed. "We had to take a candle in a lantern round somebody's neck." Joshua "never dared to tell father." In an 1897 letter, she wrote that a Captain Easter and a Mr. de Costier had talked her father out of signing a lease and into buying the property, saying "there was something on it worth his while but they could not tell him what." An unsigned 21-year lease of the cottage, dated February 25, 1835, is in the Grotto's archive. Frances had cut it up to line bookshelves. Her version of the official story: "it was really discovered in 1837, and my brother was dropped down the dome with a light. He had been through it before, but had not told father."

John Hudson, a pupil at the academy, remembered boys digging "a hole to make a duck pond" when "the ground fell in" over the Dome, in "1834 or 1835, more likely the second." He said Newlove had the hole covered and "kept it quiet" until he made the purchase. A Mr. Gore put the find in 1837, when a tool fell through an opening and a boy was lowered after it. Lucy Daniell's diary for 1844, the first recorded visit, says it was found "whilst digging a foundation for a wash house to a ladies school." By 1885, when the novelist Marie Corelli wrote it up, her guide's version had a workman's spade dropping "through a hole" and "a small boy" let down to fetch it.

Someone who nursed Frances before her death in 1909 later said she had given "misleading answers." The Grotto's present reading is that the children found it in the summer of 1835, the Dome was covered over, and 1837 was a staged second discovery once Newlove owned the land. The Historic England listing says only that it "was discovered in 1835 by a schoolmaster and his sons digging their back garden."

The listing

The Grotto was listed at Grade I on February 22, 1973, as "The Grotto," list entry 1341537. The entry opens: "Many theories have been advanced for the origin of the Margate Grotto, including Phoenician origin or a Roman Mithraic Temple." It then gives its own view: "It is however most likely to be early C19 as there are traces of a modern brick in one of the Gothic shaped arches." It describes "2 semicircular passages leading to a central dome and then a passage leading off to a rectangular chamber," with "about 2000 square yards of shell mosaic consisting of 28 different types of shells, many of which are foreign," set in cement "said to contain fish oil and crushed shells." In the rectangular chamber, it lists "motifs of the rising sun, the moon and stars."

The Grotto's own figures differ. It gives about 2,000 square feet of mosaic and 40 species, all but two native to Britain. The listing's 28 matches an 1897 survey by Frederick Stanley of the Conchological Society; John Jones counted 40 in 2012. The background infill is mostly flat periwinkle, which the Grotto says is rare on the Kent coast and was probably gathered west of Southampton. The two foreign species are in the Altar Chamber: queen conches from the Caribbean in its upper corners and giant clams from the Indo-Pacific over the altar and the entrance arch. The Grotto notes that the conches, at least, were probably set after the 15th century.

The dates

Mick Twyman of the Margate Historical Society published his case in 2006. He linked the Grotto to the Knights Templar and the mid-12th century, working from angles measured inside and the track of the midday sun on the wall of the Dome, which he reads as a calendar from March to October. He also saw features of a Masonic temple in the Altar Chamber.

An examination made in 2005, published by the Kent Archaeological Society and credited by the Kent Historic Environment Record to the Kent Underground Research Group, left the shells aside and looked at the hole. The Dome is a shaft 1 meter across and 4 meters deep with three headings off its base, which the paper calls "remarkably similar" to deneholes, small chalk mines that "tend to date from before the Roman invasion up to the beginning of the 14th century." Extending those headings into the present passages would have needed wheelbarrows, which were not common in such mines until the 17th century. Its conclusion: "a small mediaeval denehole was reworked and extended," with "an 18th century date" for the reworking "more likely," and the shellwork done then or soon after.

The Kent Historic Environment Record also carries a line that "A shell from a mosaic underground temple in Thanet was dated to AD 1670 +/- 100 by C14 dating," citing the Kent Archaeological Review for 1970 to 1971 and 1974. The record does not name the Shell Grotto, and the result does not appear anywhere else. Sarah Vickery, the owner, told the BBC in 2012 that carbon dating had been tried "and none of it's worked." The Grotto's current FAQ says the shells could be dated, but that several samples would be needed to avoid dating a Victorian repair, and the cost is high.

The Grotto's own pages disagree on whether it could have been a rich man's folly. Its FAQ argues against a rich man's folly because the land "has never formed part of a large estate." Its history page says the field belonged to the Norwood family of Dane Court from at least the mid-1500s until the Cowell family bought it in 1755. The BBC reported in 2012 that some believe the Grotto could be 12,000 years old, without saying who. The Grotto itself repeats a rumor that turtle bones found behind a wall led H. G. Wells to guess at 3,000 years, and says there is no verifiable source for it.

Gas, a bomb, and damp

Gas lamps lit the passages for nearly 100 years. A 1932 auction catalog advertised "wonderful catacombs illuminated with incandescent gas." The soot turned the shells taupe, and cleaning trials found most of them white underneath.

A German bomb hit the cottage above in 1940 and destroyed the east wall of the Altar Chamber. The Grotto dates the raid to October; the Kent Archaeological Society paper gives November 10. The wall was rebuilt in plain concrete. In 2025, the Margate artist Paul Hazelton spent more than 200 hours painting a full-size copy of the lost mosaic onto it from early 20th-century photographs, printing many of the shells with stamps cut from lino.

The garden above was concreted over in the 1980s, and the Grotto went on the Buildings at Risk Register in 1999. A conservation program began in 2007 with humidity readings above 90 percent. A leaking pipe from a neighboring property was relined, the chalk was grouted from above, and 14 metric tons of concrete roof were broken up by hand and replaced with turf. Loose mosaic was pinned back with stainless steel bars hundreds of times. The Grotto came off the register in 2012, and the conservators Rob Smith and Adrian Powell were shortlisted for an English Heritage Angel Award that year. In October 2020, the Grotto received £48,200 from the government's Culture Recovery Fund for Heritage, shared with the nearby Margate Caves, to keep both open through the winter.

The Grotto has been privately owned since its discovery. At the top of the Dome, the shaft ends in a rendered brick or flint cap with a hole about 16 inches wide, open to the sky.

The Grotto sets its hours by season. In October 2026, it opens Wednesday through Sunday, 10am to 5pm, and every day from October 21 to November 1. Visit Thanet's 2026 listing gives Thursday through Sunday, 11am to 4pm, from November through March, and daily opening from July 22 to September 6. The operator's site does not yet show winter hours, so it's worth checking before a visit between November and March.

Tickets in October 2026 cost £6 for adults, £5 for over-60s, students, and registered disabled visitors, £2 for children aged 4 to 16, and £13 for a family of 2 adults and up to 2 children. Under-4s go free. There is no pre-booking; tickets are sold at the desk. Membership of the Friends of the Shell Grotto starts at £20 a year and includes free entry. A private visit outside opening hours, with up to 1 hour in the Grotto and a 20-minute guided tour, costs £275 plus VAT.

Most visits take about 30 minutes. Staff limit the number of people underground, and at busy times the wait to go in is usually under 15 minutes. Two sets of stairs lead down, the floor is uneven with a slight camber, and there is no step-free access. The passages are confined, with limited ventilation. Backpacks and large bags are left at reception. Personal photography is allowed. Dogs are welcome in the shop but not in the Grotto, apart from assistance dogs. The museum room and shop are above ground.

There is no parking at the Grotto. The nearest pay-and-display lot is at Trinity Square, and there is usually street parking on the residential roads nearby. High-speed trains run to Margate from London St Pancras, and the Grotto is on The Loop, 8, and 32 bus routes.