The stone marker that Mason and Dixon placed at the eastern end of the famous north-south border they surveyed.

This scenic Maryland park was the site of one of the worst prison camps of the Civil War.

The celebrated eyesore created by starry-eyed sweethearts.

An immersive projection art installation uses sound, scale, and light to take visitors inside classic works of art.

This magnificent castle grew from a small Moorish fortress, and reportedly inspired two iconic Disney castles.

A rare set of strings by famed instrument maker Antonio Stradivarius is on display in the Royal Palace.

This sweet-toothed bear searching for snacks has been a symbol of Madrid for decades.

Among the oldest structures in Madrid, these Moorish walls once guarded the medieval city of Mayrit.

Over two centuries old and counting, Madrid's massive botanical garden contains one of Europe's only desert environments.

Journey through this open museum where even employees remain true to period.

The medieval woodcut-style artwork chronicles life in medieval London.

The bronze uniforms commemorate the vital role of women during World War II.

These mysterious Viking chess pieces spent centuries hidden on a remote Scottish island.

This pub was 238 years old when it decided to revamp its image: It started serving Thai food.

The ritual has been performed uninterrupted for nearly 700 years.

A statue of the legendary Celtic warrior queen who fought the Roman invaders stands in one of the cities she once destroyed.

Tucked away in the Tower of London is the weapon once used to execute high-profile prisoners.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

The cedar tree in Highgate Cemetery earned its title by accident.

A historic house left in "dramatic still life."

This London pub hides a peculiar secret: a recreation of the rooms shared at 221b Baker Street by Sherlock Holmes and Dr. Watson.

An easily overlooked stretch of ornate window fronts and gaslight lamps that could be right from the pages of Dickens.

It is said the legendary wizard once lived in this sea cave beneath Tintagel Castle.

A curious memento mori hangs in the magnificent Cathedral of Segovia.