This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

A special shop catering to the needs of things that go bump in the night, and also helps kids become writers.

A vast overgrown cemetery, once known as one of London's "Magnificent Seven."

Wedged between two buildings at the Great Ormond Street Hospital is this secret music installation.

A student driver's nightmare.

A hands-off space for graffiti artists to hone and display their skills.

An easily overlooked stretch of ornate window fronts and gaslight lamps that could be right from the pages of Dickens.

This collection of illusory paraphernalia has been culled from the history of London's premier magician's club.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

This churchyard arbor is surrounded by hundreds of gravestones placed there by author Thomas Hardy.

A kaleidoscopic warehouse-maze of handmade neon signs.

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

See some of the world's greatest racing horses at this idyllic thoroughbred breeding facility and garden complex.

An ancient holy well said to be used by the patron saint of sailors and travelers, lost in the boggy west of Valentia Island.

A spectacular hidden beach in Ireland has the dark, disturbing nickname of "Murder Hole Beach."

Oliver Cromwell once seized the land under this house, which included the ruins of a medieval abbey that the owner used to build his stately home.

Ireland's most remarkable collection of these curious cone-shaped houses is worth the buzz.

An important pilgrimage site for pagans and early Christians, named for a Celtic goddess-turned-saint.

The world's tallest box hedge is found in a delightful garden.

This Irish museum in a historic 19th century market pays tribute to the glory of butter.

After being destroyed by IRA sympathizers, the ruins of this stately Irish manor have sat vacant for decades.

A moody and picturesque riverside ruin overgrown with vegetation.

This controversial Irish show cave is home to a massive formation known as the Great Stalactite.