Below a historic English market town lies a secret underground city complete with kitchens, laundries, storerooms, and an underground lake.

Scotland's only funicular railway is also the United Kingdom's highest.

In Twickenham sits a small whitewashed castle that inspired Mary Shelley's 'Frankenstein.'

This crumbling folly looks like an enchanted left over from Middle Earth.

Ruined castle with subterranean vaulted Goblin Ha' or "Goblin Hall."

The secret wartime bunker built on the platforms of an abandoned Tube station.

This elaborate Byzantine-style building was designed for a not-so-pretty purpose.

One of Scotland's most important modern structures, it just made the '100 Most Endangered Sites' list.

This short bridge is the only thing connecting a tiny Irish island to the mainland.

A 4,500-year-old forest is slowly being revealed from beneath the sands of a Welsh beach.

This haunting stone chasm is a hotbed of mossy rock and English legend.

The remains of a grand castle that may have inspired Bram Stoker's Dracula.

Lovers proclaim their unbreakable bond by leaving their names on locks fastened onto the Shoreditch fence in East London.

A open air theatre built on a cliff by an eccentric British woman.

Besieged by war, this castle ruin has crumbled into a peaceful picnic spot.

Three bridges straddle a stream, one stacked upon the other.

This well-preserved Cistercian Abbey in a romantic pastoral setting has inspired artists like the poet Wordsworth.

A hermit's tiny cell built into the cliffside that saved him in South Pembrokeshire.

The mystery of this small, brick pond eluded its possibly only investigator until his death.

Tombstones and enigmatic inscriptions hide within a vault beneath a popular London arts venue.

England's oldest surviving hedge maze has been confusing visitors for over 300 years.

A breathtaking flower tunnel bursts with beautiful golden blossoms.

The ruins of an 11th-century Norman castle with a rare, perfectly circular shape.

Grab a cuppa at England's first and only domestic tea plantation.