A harem-inspired Moorish fantasy design in a Victorian-era Welsh castle.

A modern English garden of eccentric beasts, follies, and oddities.

Accessible only at low tide, the deserted island is dotted with World War II ruins.

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 fantastic castle rumored to be the birthplace of King Arthur.

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

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.

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

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

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

The atmospheric road was never meant to be so creepy.

The world's largest collection of witchcraft regalia.

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

These fantastically named natural pools look like something out of a Scottish myth.

The mysterious, fantastical woodland inspiration for "The Lord of the Rings."

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

This mysterious hilltop collection of Druid carvings isn't quite what it seems.

Semi-precious Blue John stones have been mined in this cavern system for centuries.

A gorge full of caverns where early humans lived alongside cave hyenas, giant mammoths and wooly rhinoceroses.

This beautiful "lagoon" is actually a toxic soup filled with cars, carcasses, and trash. When warnings couldn't stop people from going for a dip, the town dyed it black.

A 13th-century fortified manor house that was once sieged during the English Civil War.

The gravestone of a delicate singer-songwriter bears a fittingly introspective epitaph.