This hidden green space is the city's second largest conservatory.

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.

Mysteriously stacked storefront paths give this medieval British town an iconic style like none other.

Islanders once used this dramatic, otherworldly landscape to hide their cattle from Viking raiders.

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

The largest greenhouse in the world is home to over one million types of plants.

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

A Victorian natural history and ethnographic museum with wonderful turn-of-the-century, science-book-esque evolution displays.

A unique waterfall that some believe attracts the fairfolk.

A 2000-year-old Roman amphitheater lies just below Guildhall Yard.

The largest of London's subterranean rivers and once a mad, bad center of London life.

The ruins of this gorgeous clifftop castle look like something from a fantasy novel.

Surreal riveted sea forts once protected the Kent shores from German attack.

The remains of Crystal Palace Great Exhibition of 1851.

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

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

Spend the night in this formerly abandoned traditional Scottish village.

The final resting place to 300 Victorian-era pets hides inside the city park.

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

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

Hear the quietest sound from across the dome.

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.