Two plaques commemorate the site of Shakespeare's first theatre.

Claiming to be the oldest hat store in the world, this historic haberdashery had a hand (and a head) in the creation of the Bowler.

Near the former site of numerous witch burnings, this lavish Edinburgh mainstay pays homage to Scotland's brutal history.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

This legendary stone is of unknown origin, and throughout history has been a literal touchstone for British leaders.

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.

Giant, friendly pelicans in Central London, the most unlikely of places.

Hear the quietest sound from across the dome.

Several plaster noses are hidden in plain sight around London's Soho neighborhood.

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

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

The sign at the garden gate reads: “These Plants Can Kill.”

The Adriatic's most famous wind can be reliably experienced in the city's Marina.

During World War II, this rice mill became a Nazi concentration camp.

Hidden in an Italian forest is a completely homemade amusement park that has taken a lifetime to create.

This Italian foot path winds through the mountains via 52 individual tunnels.

2300-year-old Roman road connecting the empire.

This bustling Italian plaza is built on the ruins of an ancient Roman amphitheater.

The ruins of the largest gladiatorial school in Rome are largely hidden under modern streets.

Built on a medieval synagogue, this church has a burial crypt, tunnel system, and Jewish ritual bath hiding deep underneath.

A submerged archeological park still holds the wonders of a Roman Sodom.

This quaint Italian town keeps losing ground as the sides of its plateau slowly erode.

Water and windows define this defensive Italian well.

This picturesque Umbrian city has a subterranean side that has long remained hidden.