This 1920s Dutch barge is now a floating bookstore.

Ancient cliffs resembling a kilt on Scotland's second largest island emit an entrancing sound.

Tiny effigies of the victims of Edinburgh's famous Anatomy Murders.

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

The signs of a long buried road can still be found hidden beneath a London sewer grate.

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

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

A historic house left in "dramatic still life."

Now famous as the "Harry Potter bridge," this impressive concrete viaduct has long been an icon in its own right.

The anatomical-pathological collection of a man who changed surgery.

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

A makeshift shrine to the late rock star is still kept up on the nondescript façade outside 1 Logan Place.

This castle was established by the 4th Duke of Montrose and is connected to the Buchanan Clan.

This tangled English forest looks like something right out of a fairytale.

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

The world's first underground farm is in a World War II bomb shelter beneath the streets of London.

Catacombs turned marketplace.

Spend the night in this formerly abandoned traditional Scottish village.

The longest hedge maze in the world.

An ancient Scottish rock formation said to be the gravesite of a giant remains ensconced in legend and intrigue.

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

A strange rock with a sinister reputation lurks within the crimson waters of this Scottish glen.

Amazing and mysterious Neolithic settlement on Scotland's Orkney Islands.

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