This grand stone tower was dedicated to a famed American humorist almost by coincidence.

The Denver airport is guarded by a 32-foot-tall sculpture of a demonic horse.

In Zanzibar, a historic 19th-century palace is a reminder of the world's shortest war.

On holy holidays, Israel's second president used this room atop Mount Zion as a refuge to read the Torah.

Two thousand artifacts from around the world collected by one woman who loved to travel.

"the sweltering inhabitants of Charleston and New Orleans, of Madras and Bombay and Calcutta, drink at my well . . . The pure Walden water is mingled with the sacred water of the Ganges."

This supermarket is suspended 25 feet above an interstate highway.

A free, public museum dedicated to the fascinating science of sight.

This quirky UFO-shaped curiosity is often mistaken for the airport’s control tower.

A dark patch of the ceiling at Grand Central Terminal which was not restored is still stained brown by tobacco.

Hidden in an ordinary Midtown building is a one-room museum dedicated to the greatest escape artist.

The New York hotel where tragic visionary Nikola Tesla spent his final hours, destitute and alone but for the pigeons.

At 135 years old and counting, this historic print shop is heaven for poster nerds and music buffs.

The self-proclaimed world's smallest museum, located next to a Massachusetts sandwich chain.

This hidden sculpture garden full of Wild West art is one of San Antonio's best-kept secrets.

A memorial to the first person killed by a motor vehicle in the Western Hemisphere.

The headquarters of one of the world’s longest-running humor magazines bears a noticeable resemblance to a head wearing a Prussian helmet.

The mastermind behind this palatial hotel perished on the Titanic weeks before its grand opening.

This stunning blue and gold room changed cities twice before becoming part of the Smithsonian.

It may look like no more than a full-scale model, but every part of this full Space Shuttle stack had a working role in aviation history.

An uber-secure, windowless tower of doom in the center of Manhattan is an NSA spyscraper.

A propulsion engine testbed that paved the way for the Space Shuttle launch sits without recognition at this rocket center.

One of the oldest used bookstores in the U.S. has been selling antiquarian treasures since 1825.

A quirky bookstore hidden beneath a sea of whitewashed Greek villas.