A island reachable by a causeway at low tide is possibly one of the earliest Western European locations to be identified in text.

This series of Scottish caves has no clear purpose other than baffling historians.

Perfectly preserved ancient monastery in an impossibly dramatic location on a rocky island in the Atlantic.

The longest hedge maze in the world.

Several plaster noses are hidden in plain sight around London's Soho neighborhood.

One of the oldest scientific gardens in Britain, containing more than 13,302 plant species in its core collection.

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

The fountain marks the area where hundreds of accused witches were burned at the stake.

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

Rebuilt remains of a temple to Roman god Mithras.

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

The only university zoological museum in London houses extinct animals, bizarre natural history specimens, and a Micrarium of microscopic creatures.

An unusual round church in London with a Templar past.

Ruined 11th century abbey built by King David I in Edinburgh, Scotland.

A subterranean ice warehouse that has lain hidden beneath central London for over a century is now open to the public.

The atmospheric road was never meant to be so creepy.

A tongue-in-cheek arcade where the games are based on everyday life.

This London pub hides a peculiar secret: a recreation of the rooms shared at 221b Baker Street by Sherlock Holmes and Dr. Watson.

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.

The hidden "ballroom" under a mansion lake was built by a criminal who ate a cyanide pill during his trial.

The world's largest collection of witchcraft regalia.

Banksy gives themself artistic license with this piece of London street art.

Hidden beneath the streets of London is a secret subway that only carried mail.

Winding paths and ramshackle mausoleums in the oldest "park cemetery" in London.