The birthplace of Karl Marx is now a museum dedicated to the communist revolutionary's life and work.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

The television series' iconic giant foot was borrowed from this classical painting.

This neo-Gothic former auto showroom is one of the few remaining reminders of Brooklyn's "Automobile Row."

The oldest living tree in Manhattan comes shrouded in sinister legend.

The notorious headquarters of a corrupt political machine.

Test your business savvy and play the market for cocktails at this stock exchange-inspired watering hole.

The tiniest little stage in New York.

Cheap pizza and all of your naughty bedroom needs housed in a stunning example of Art Nouveau architecture.

There must be a pun in this haystack somewhere...

Tucked away amidst some of the most famous addresses in the world is New York's only fraction of a street.

A 19th-century politician who died after walking home in a blizzard is honored with this Manhattan statue.

New York's oldest concrete structure is being preserved thanks to the gentrification of Whole Foods.

Dedicated to the history and culture of smoking, this small museum now includes a vape lounge.

One of the few remaining American elm trees in New York’s Tompkins Square Park was the birthplace of a new religion.

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.

Manhattan’s Battery Park has a whimsical carousel full of spinning, glowing fish.

Manhattan's deadly West Side railroad, which killed hundreds of New Yorkers, is remembered by this simple plaque.

Noirish green neon marks the location of one of the oldest private detective agencies in France.

This stunning French estate was so lavish that it landed its original owner in jail for the rest of his life.

Michael Jackson got Bad and Crocodile Dundee walked on heads in this iconic Brooklyn subway station.

This Fifth Avenue church has long been the favored worshiping place of Broadway actors and vaudeville performers.

In the best of all possible worlds, everyone will get a chance to see this statue in which Voltaire's heart is interred.

The Underground Railroad passed right through this historic Brooklyn Heights church.