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

Now home to a drinking establishment, this building has a macabre history.

This otherwise ordinary close on the Royal Mile constituted the end of the world for Edinburgh’s poorest residents.

One of Ireland's most infamous prisons for rebels including men, women and children.

The ancient tomb acts as a calendar that keeps perfect time.

This Irish show cave is said to have been the site of a Viking massacre that claimed 1,000 lives.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

This Slovakian statue of an emerging sewer worker might just be a bronze peeping tom.

The "dragon babies" of southeastern Europe.

The walls of this medieval church are covered with perfectly preserved frescos, including a pristine example of the Dance of Death.

A whimsical bridge adorned with decorative dragons.

A miniature train-ride through Slovenia's largest cave system.

This one-time health resort was used by aristocrats around the world.

This massive subterranean fissure is known as the "underground Grand Canyon."

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

This scale model of our solar system hid in plain sight for years before a physics team sought out all the planets.

This giant middle finger statue sends an unambiguous message to Italy's bankers.

These spooky and unusual stone formations create an underworldly landscape.

The tallest outdoor elevator in Europe rockets passengers on a dizzyingly precarious ride to the top of a mountain.

Stone Age solar temple is aligned with the sun on each equinox and solstice.

An abandoned set from the 1980 film "Popeye," claimed and repurposed as a theme park by creative locals.

One of the best-preserved Roman amphitheaters is still used today, but for less brutal events.

Steadily reminding Czechia of its past.

A series of playful yellow penguins share a serious message about the environment.