Italy's curious field of mud volcanoes is named for being both gross AND salty.

The legendary luxury train passage is commemorated with a charming museum inside its former eastern terminus.

This Tuscan lake hides a 13th century town that is still visible when the water recedes.

A monumental statue of RCA's mascot now sits atop a historical society roof after a life of moving around.

This mountaintop observatory is home to one of the world's largest reflective telescopes.

Unsurprisingly, Holland is home to one of the most magnificent flower gardens in the world.

Once a favorite playground for the world's most illustrious guests, Hotel Nacional's secret weapons and bunkers reveal a more menacing side to its golden history.

According to legend, this boat-shaped henge is built over the grave of a mythic king.

According to the locals, the sands of this secluded Norway beach are infused with gemstone particles.

Take a stroll through the hellish grotesques of Hieronymus Bosch in this elaborate Netherlands church.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

The picturesque birthplace of Icelandic democracy is drenched in the blood of its brutal past.

This Buddhist temple is home to the graves of the Japanese national legends, the 47 Ronin.

This Danish rock field is actually a sprawling ancient cemetery holding the bodies of 700 Vikings.

This ancient Irish tower could easily have stood in for Rapunzel's prison.

The bar where "The Great Train Robbery" was planned was once a nexus of high society and low morals.

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

On this tiny spot of land in the middle of Lake Titicaca the only ones who do the knitting are the men.

This remote island village was in danger of depopulating completely until a tunnel was built to connect it to the rest of the world .

Hidden away in the city of Madison, Wisconsin is a nearly forgotten home that Frank Lloyd Wright built for a childhood friend.

This domed temple was built in a hidden cave mouth as a refuge for sinners seeking absolution.

This controversial Irish show cave is home to a massive formation known as the Great Stalactite.

These numerous Israeli caves were dug out over hundreds years for reasons ranging from hideouts to burial sites.

These crumbling Nazi artillery bunkers are now fair game for massive graffiti projects.