Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

On the Oregon coast there is a natural hole that seems to be draining the sea.

Illegal drag racing two stories beneath Chicago’s streets.

When you visit his grave, be sure to rub the Great Emancipator's nose for good luck.

Not to be confused with the iconic New York City skyscraper, this Chicago building is a vibrant hub for artists.

A 200-year-old building in the French Quarter that was to be Napoleon's home in the New World.

The first park built over a freeway is a brutalist masterwork.

The hotel where Martin Luther King Jr. was shot is now a museum dedicated to his work.

Most-visited and most-photographed slot canyon in the American Southwest.

This stoic, if derpy, giant stands as a monument to Oregon's statehood and the novelty culture of yesteryear.

This extravagant Art Nouveau rest stop features a million-dollar view of the Columbia River.

A beautiful 62-acre Catholic shrine and botanical garden.

A walk-in working camera obscura produces 360-degree live images of the San Francisco coast.

Residents of Fremont in Seattle have considered it the center of the universe since the 1970s.

A massive volcanic plug is now a protected area that hosts a number of bird species.

A winding path built in secret on the edge of the continent.

A sculpture of the famous photograph stands on San Diego's "Greatest Generation Walk."

The final resting place of a space program monolith.

The trials and tribulations of marking Poe's grave.

Not merely a museum – but a whirring powerhouse that offers a subterranean peek into the heart and soul of cable car operations.

A modernist landscape of water and sci-fi concrete.

A hotel and restaurant serving as the mecca of kitsch.

This whimsical Oz-themed park had a wonderful impact on the surrounding neighborhood.

The only arched bridge made of stone on the entire Mississippi River.