A hidden "place of interment for gentlemen."

Elevated freight railway turned wildly successful urban park.

One kilometer of thick brass rod laid out before your eyes.

A terrific purveyor of natural history objects and curios.

Plot your trip through the city on the sidewalk.

Salute the leader of the proletariat.

A room in New York City that contains 250 cubic yards of dirt worth a million dollars.

Red frames showcase remnants of one of New York's original subway stations.

The most confusing clock in New York.

The site of the deadly Triangle Shirtwaist Factory Fire.

Touching mementoes from those who didn't make it back from World War I still hang in one of New York's oldest bars.

This exemplar of modernist architecture is meant to captivate and inspire students of the Cooper Union.

A tiny piece of the Moon is embedded in this stained glass masterpiece.

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

At 207 feet, one of the world's longest continuous escalators.

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

Wisconsin's most celebrated export gets the royal treatment on I-94.

A place to eat for on-the-run agents and espionage enthusiasts.

A sealed test tube said to hold Thomas Edison's dying breath was given to the inventor's friend and mentee, Henry Ford.

The only surviving prototype for Buckminster Fuller's house of the future.

One man's attempt to create an artistic wonder on a run-down block in Detroit.

Controversial tribute to the heavyweight champion boxer who grew up in Detroit.

These enduring murals depicting a distinctly Marxist tribute to capitalism could not even be defeated by McCarthyism.

The most famous location in China was home to whole dynasties worth of imperial rulers.