Hidden behind a wall for decades, this masonic lodge was only rediscovered during renovations.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

A mysterious pair of mice eating a piece of cheese is London's smallest public sculpture.

Abstract dinosaur models in London.

An artistic tribute to the famous singer, just around the corner from where he was born.

A unique waterfall that some believe attracts the fairfolk.

An Oxford museum where visitors can have tea with the Mad Hatter and climb through the wardrobe to a fantasy land.

After nearly 60 years, there's still a bear at Paddington Station looking for help.

A mysterious artist-run cabinet of curiosities and library.

400-year-old garden, restored to beauty.

Hidden in a grotto 26 feet below Nottingham's oldest hotel, this stylish subterranean drinking den is notoriously hard to find.

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

Hear the quietest sound from across the dome.

In this cobwebbed old operating theater, you can practically hear the screams of the unanesthetized patients.

The longest hedge maze in the world.

An incarceration museum on the spot of possibly the oldest prison in England.

A historic London pub with prison cells in the cellar and a "spy room" on the second floor.

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

A little slice of Japan and its aesthetics in London's Holland Park.

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

Catacombs turned marketplace.

Famously misunderstood wonder of the ancient world

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

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