A labyrinthine network of chambers with a storied past hides below Edinburgh's South Bridge.

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

This tidal island, a sacred site in early English Christianity, was the target of a notable Viking invasion.

This iconic 1,000-year-old medieval castle is a favorite of the film industry, most notably as the location for Hogwarts in Harry Potter.

This beautifully situated lakeside Roman settlement was likely built during the reign of the Emperor Hadrian.

Also known as "Robin Hood's tree," this tree became a famed location along Hadrian's Wall before it was cut down in an act of vandalism.

Locals call it the "Give Peas a Chance" bridge because of its distinct graffiti.

The remains of a World War II-era Japanese American internment camp dot a windswept Colorado hill.

The largest self-built castle in the U.S., six decades in the making.

In memory of the 110 victims of ValuJet Flight 592 that crashed in the Everglades.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.

A small poultry graveyard in the courtyard of a popular Key West watering hole.

This legendary "evil" doll has been haunting the citizens of Key West for over 100 years.

Where monkeys run wild and the humans are caged.

The comedy and tragedy of Oscar Wilde is preserved in a Dublin park, captured in a sculpture of colorful stone.

A small horde of mythical creatures lurk almost imperceptibly within the museum's wildlife dioramas.

One of the oldest remaining Catholic churches in England is home to the hand of a 7th-century saint.

The John Snow Memorial marks the epicenter of London's 1854 cholera epidemic.

A naturally mummified 2,000-year-old man.

The signs of a long buried road can still be found hidden beneath a London sewer grate.

This coffee shop lies hidden beneath a historic church.

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

One of America's founding fathers lived in this London lodging between 1757 and 1775.

A building so large that it has its own weather.