The walls of the iconic dome are hollow and have a secret stairway.

This lonely waterfront memorial to the men of the Titanic was erected by the "Women of America."

A nostalgic bibliographic gem.

A lovely aquatic park built by a one-armed Civil War veteran who made a fortune from lotuses.

A derelict bit of transportation infrastructure hidden in the woods.

A painfully obvious spy house sits right across the street from the Russian Embassy.

During the Industrial Revolution this “Temple of Invention” was full of intricate miniature machines and gadgets.

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

Home to items never before seen by the public.

The site of the climactic scene from the classic horror film is now a historic landmark.

This historic recreationist school churns out warriors that may very well have had a fighting chance in Rome's pits of the day.

This delightful little museum is dedicated to only one thing: pasta.

The yawning maw of this pagan visage is said to bite off the hands of liars.

One of the most photographed buildings in a city known for its Modernista architecture is an abandoned squat.

One of Europe's largest supercomputers is housed inside of a disused chapel.

Step inside the first house designed by Catalan architect Antoni Gaudí, considered to be one of the first Art Nouveau buildings.

Mountain where Jesus was first tempted by the Devil.

This cemetery features modernist statues as strange as its name.

Gaze upon chocolate sculptures depicting everything from chariot races to Gaudí's famous church at this shrine to sweets.

A beautiful but toxic fountain of mercury.

This semi-secret storybook hedge maze is also the oldest garden in the city.

Established in 1638 to battle the Black Death, Hortus Botanicus Amsterdam is a treasure trove of rare flora.

A floating cat sanctuary on an Amsterdam canal.