The secret city built by the Manhattan Project.

This former train tunnel is filled with lines from a poem crafted by Robert Louis Stevenson.

This underpass became an unlikely piece of cinematic history after its appearance in 'A Clockwork Orange.'

Decades of discarded bottle caps line this alleyway, a fixture of Texas A&M.

The abandoned zoo enclosures offer a perfect place to experience the other side of the bars.

The remains of an idyllic small town built for the film 'Big Fish' still stand around a rundown main street.

The largest underground pedestrian tunnel system in the U.S. mostly caters to the people working in the offices above, but provides a great, air-conditioned way to traverse the city.

Local arts organization founded in a former church.

An emerald-green grotto just a short trip from Austin.

A symbol of Texas pride.

An entire subdivision was accidentally built on a flood plain, resulting in its eventual demolition—but the streets are still there.

Lewis Carroll's White Rabbit or something else altogether?

This iconic L.A. bookshop is housed in an abandoned bank—both symbolic and chic.

D.C.'s first central library was born out of a chance encounter with the philanthropist whose name it bears.

These slanted cubic abodes are a creative if odd solution to a zoning pickle.

Some of the best pastries in "the Czech heritage capital of Texas" come from a gas station off I-35.

The largest whale museum in Europe allows visitors to walk among life-size giants.

Nature's biggest mammal swims in landlocked Oklahoma.

This grimly-titled Texas cemetery is all that remains of a Wild West settlement with possibly the worst name.

A spur fit for a giant sits just off Highway 281 in Texas.

Fine dining 20 feet below the surface in the Indian Ocean.

This water tower slanted at an uncomfortable angle off the old Route 66 was an ingenious marketing ploy.

A time-capsule monument reminding future generations of the importance of efficient and effective use of natural resources.

These half-buried combine harvesters just off Route 66 are an homage to the Cadillac Ranch.