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

This off-limits room in the National Library of France is home to a system of pneumatic tubes, once used to bring books to readers.

This crumbling, graffiti-covered mansion sits tantalizingly within reach of the proletariat who frequent a public park.

Avant garde house of Pierre Cardin on the Cote d’Azur.

The mental institution where Van Gogh created some of his most famous work now allows guests to walk in the artist's footsteps.

An aluminum skeleton brings Chinese mythology to the French shore.

A scandalous Art Nouveau collaboration that set Paris all atwitter at the turn of the century.

Dedicated to the art of hunting, with juxtapositions of contemporary art.

One of the greatest maze designer’s greatest mazes.

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.

This massive library holds what was once the largest book collection in the world.

Paris' fabled purveyor of exotic taxidermy and natural history curios.

This French ghost town from World War II has been left as a memorial to German atrocities during World War II.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

Abandoned railway line circling the city of Paris.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

This 220-year-old house is a reminder of New York City's Dutch past.

The artist and New York City icon lived, worked and died in this converted carriage house owned by another iconic artist, Andy Warhol.

Monument to a forgotten NYC disaster that claimed the lives of 1,000.

A simple midtown bar was once the home of a secretive and exclusive club staffed by "bunnies" under Hefner's strict rules.

A drawbridge named for a potentially intersex Polish national who fought alongside George Washington during the American Revolution, and an example of "Pulaski Red".

A small part of lower Manhattan is actually made from a bit of England.

The famous facade of Grand Central Terminal hides a regulation tennis court, and it's not the first one.

New York's oldest and possibly grandest keeper of books.