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

A doctor had this large tub carved into rocks to facilitate easier seawater bathing.

Once used to protect important Roman trade routes.

A Victorian Gothic masterpiece housing a world-class collection of rare books and manuscripts.

When the city of Manchester built a new centralized heating network, they did it with style.

This chain of artificial lakes was an ideal test ground for the aircraft that would carry the "bouncing bombs" used by the WWII "Dambusters" squad.

A series of carved figures that scandalized British society.

The broken skateboards that became a poignant memorial to a murdered skater.

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

A labyrinth hides in plain sight at each of the city's 270 Tube stations.

The sculpture of the deceased cockatoo flops atop its personal plinth.

No one knows who created the statues or if they are arranged properly—let alone the artwork's real name.

A gallery specifically dedicated to the botanical illustrations of a remarkable traveling lady.

The last remaining example of the boatmen's perches that once dotted the south bank of the Thames.

This astronomical clock is the second oldest in England.

The oldest residential street in Europe also features an optical illusion.

This restaurant's specialty is "a major enigma for food historians."

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

This grand manse has been transformed into a museum devoted to one of the founders of Fantastic Realism.

The solemn exterior conceals an opulent interior of this 17th century church.

In the middle of a Vienna square, Roman ruins dating back some 2,000 years are on display.

The Habsburgs' royal collections of art and wonders.

Vienna's diversity-themed traffic lights were inspired by the Eurovision Song Contest.

A spherical "micro-nation" in the heart of Vienna.