The second building of its name to occupy this location might be the finest flatiron building in San Francisco.

San Francisco's oldest surviving monument and meeting place for 1906 survivors.

This concrete tangle of square pipes has stood as a proud thorn in the city's side since the '70s.

A hidden garden of stones engraved with scriptures, a Joseph Smith Sphinx, all carved by one man.

Oddly shaped rock formation, misassociated with a nearby utopian community.

A breathtaking array of ancient Pueblo structures and artifacts counterintuitively preserved by neglect.

Legends surround this jagged rock formation in the New Mexico desert.

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

A towering tribute to decisiveness stands on the spot where Brigham Young and his followers decided that this must be the place.

Largest man-made excavation on earth!

There’s a hidden military meme engraved on the World War II Memorial.

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

Yo, Adrian!

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

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

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

Allowing humans and fish alike to migrate from freshwater to saltwater and back again.

Belly up to the bar in Cowtown, don't forget to buy some boots.

A modernist landscape of water and sci-fi concrete.

The Grand Canyon of Texas.

The top of a giant mesa, just outside of Amarillo, appears to float in the sky above.

A sculpture made of 10 Cadillacs as a monument to the "Golden Age" of the American automobile.

Golden plates containing what would become the Book of Mormon were believed to be buried on this New York hillside.