The Secret

The dossier

Every secret so far

25 hidden places across Britain — each one real, each one checked, each one worth the detour. Another 55 wait in the vault, released one a week.

№ 01Kent

The Shell Grotto

A subterranean passage lined with 4.6 million shells — and nobody knows who built it, or why.

UndergroundDeclassified
№ 02Cornwall

St Nectan's Glen

A sixty-foot waterfall that has drilled clean through a rock basin, in a ravine held sacred for centuries.

WaterfallDeclassified
№ 03Inner Hebrides

Fingal's Cave

A sea cave built from hexagonal basalt columns so perfect the Victorians assumed it was architecture.

CoastDeclassified
№ 04Sutherland

Sandwood Bay

A mile of roadless pink-tinged sand guarded by a sea stack — the four-mile walk in keeps it nearly empty.

BeachDeclassified
№ 05Gloucestershire

Puzzlewood

Fourteen acres of moss-drowned ravines and twisted yews that filmmakers borrow when they need another planet.

WoodlandDeclassified
№ 06London

Postman's Park

A pocket park in the City hiding a Victorian memorial to ordinary people who died saving strangers.

CityDeclassified
№ 07Yorkshire Dales

Gaping Gill

One of Britain's biggest cave chambers opens to the public twice a year — by winch, straight down the waterfall shaft.

UndergroundDeclassified
№ 08Fife

Culross

A seventeenth-century Scottish burgh preserved so completely that film crews barely need to dress it.

VillageDeclassified
№ 09Pembrokeshire

Skomer

An island where puffins own the paths and the world's biggest shearwater colony sleeps underfoot.

IslandsDeclassified
№ 10Stirlingshire

Finnich Glen

A hundred-foot gorge of blood-red sandstone hiding a preacher's rock they call the Devil's Pulpit.

GorgeDeclassified
№ 11Staffordshire

Lud's Church

A hidden chasm so green and strange it may be the Green Chapel of Arthurian legend.

GorgeDeclassified
№ 12Kent

The Denge Sound Mirrors

Three concrete ears on the Kent marshes, built to hear enemy aircraft before radar made them obsolete.

RelicDeclassified
№ 13Caithness

The Stacks of Duncansby

A mile past the John o' Groats signpost: sea stacks, a slot canyon full of seabirds, and almost nobody.

CoastDeclassified
№ 14Isle of Skye

Loch Coruisk

A loch sealed inside the Black Cuillin, reached by open boat — or a scramble the guidebooks call the Bad Step.

LochDeclassified
№ 15Slate Islands

Easdale

The tiny island that roofed the world — now home to sixty people and the World Stone Skimming Championships.

IslandsDeclassified
№ 16Carmarthenshire

Llyn y Fan Fach

A black glacial lake whose fairy bride left three sons — and a real dynasty of medieval doctors.

LakeDeclassified
№ 17Cheshire

The Anderton Boat Lift

A Victorian cathedral of iron that picks up canal boats and lowers them fifty feet to the river below.

IndustrialDeclassified
№ 18Llŷn Peninsula

Bardsey Island

The island of twenty thousand saints, reached by a boat through a tide race at the end of Wales.

IslandsDeclassified
№ 19Devon

Lundy

A granite island in the Bristol Channel with puffins, a ghost lighthouse — and its own postage stamps.

IslandsDeclassified
№ 20Shetland

St Ninian's Isle

Britain's largest sand causeway leads to an island where a schoolboy dug up a hoard of Pictish silver.

BeachDeclassified
№ 21Norfolk

Grime's Graves

A lunar field of craters in the Breckland — and a nine-metre ladder down into a Stone Age flint mine.

UndergroundDeclassified
№ 22Suffolk

Orford Ness

A shingle spit where Britain tested bombs and radar — now the loneliest nature reserve in England.

CoastDeclassified
№ 23North Yorkshire

Mother Shipton's Cave

England's oldest paying attraction: a waterfall that slowly turns teddy bears, hats and bicycles to stone.

CuriosityDeclassified
№ 24County Antrim

The Gobbins

An Edwardian cliff path of tunnels and iron bridges bolted to the Antrim coast — lost for decades, now rebuilt.

WalkDeclassified
№ 25County Fermanagh

Marble Arch Caves

A river runs through it: caverns of streaked limestone crossed by boat, under the Fermanagh hills.

UndergroundDeclassified