The world's longest known cave system.

At 135 years old and counting, this historic print shop is heaven for poster nerds and music buffs.

Knoxville’s architectural icon was the symbol of the 1982 World’s Fair, even catching the googly eye of Bart Simpson.

This high point in the Great Smoky Mountains is said to be home to the chief of all bears.

An ode to "The Queen of Appalachia."

This chestnut box will not be opened until the country music legend's 100th birthday in 2046.

A bizarre roadside attraction and the first instance of miniature golf in the world.

This massive store is home to an eccentric collection of vintage, retro, and peculiar goods.

A whimsical bridge uses saxophones to pay tribute to two great men and the European Union.

Somewhere there is a giant who can no longer poop, but now travelers can stay inside his anus.

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

"Respectful to the dead, safe and sanitary to the living, dedicated to the Genius of Memory..."

This stately monument has been wearing a traffic cone hat for decades much to the delight of the locals.

Displaced highlanders would take shelter from the wet Scottish climate under the large walled bridge at Glasgow Central Station.

Overlooked by many, the two famous Scottish warriors guard the main gate of Edinburgh Castle.

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

The most loyal of little dogs, or a Victorian era publicity stunt?

This 17th-century street hidden beneath Edinburgh was once a breeding ground for the black death.

Edinburgh's oldest statue hides within a parking lot behind the city's iconic cathedral.

Giant topiary dog once played a role in a terrorist bomb plot.

The oldest restaurant in the world is this old-world Spanish eatery, still known for its suckling pig.

This ancient theater was once the home of fierce gladiatorial battles.

This statue was given to France by the United States to commemorate the centennial of the French Revolution.

The spiral staircase hidden inside this giant Parisian column was likely built for Catherine de Medici's astrologer.