A subterranean playground in an abandoned slate mine.

The true age of this ancient stone circle is unknown, but its stunning vista isn't in question.

This 1920s Dutch barge is now a floating bookstore.

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

A fantastic castle rumored to be the birthplace of King Arthur.

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

400-year-old garden, restored to beauty.

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

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

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.

Northern Ireland's Brobdingnagian stepping stones.

360° views of the city plus five floors of optical illusions and hands-on science.

The atmospheric road was never meant to be so creepy.

A 30-acre garden inspired by the principles of modern physics.

Famously misunderstood wonder of the ancient world

The world's largest collection of witchcraft regalia.

The most iconic structure in Scotland has been home to bishops, colonels, and Sean Connery characters.

This historic island prison holds one of the dungeons from the Count of Monte Cristo even though it is a work of fiction.

A self-built mosaic house and sculpture park.

Sleep in a climate-controlled plastic bubble for the night.

The great Italian Renaissance painter was laid to rest here in the Chapel of Saint-Hubert.

The mental institution where Van Gogh created some of his most famous work now allows guests to walk in the artist's footsteps.

Science fiction's grandfather has a fittingly marvelous tomb.