This narrow coastline trail through the dense Kauai wilderness is among the most beautiful and dangerous in the world.

In the middle of an extremely unforgiving and desolate high desert is the most secret military facility in the world.

The arch that celebrated the completion of the Lincoln and Victory highways.

This beloved roadside attraction welcomes visitors with his signature neon smile.

A sprawling cave network created by a lone lava tube.

The longest continuous lava tube in Oregon.

An optical illusion found amid a logged redwood forest.

A cozy bookstore is tucked within an old gold mine shaft beneath the cafe and ice cream shop.

Once a staging site for World War II munitions.

Oh, just a motel on the edge of the desert decorated with thousands of clowns conveniently located next to an abandoned graveyard.

An eatery for UFO seekers on the Extraterrestrial Highway.

This sign designates the road that leads to the infamous Area 51.

Mysterious meeting place for UFO hunters near Area 51.

A unique museum where guests can rent and operate a locomotive.

The viewpoint for this attractive, off-the-beaten-path waterfall is reached by a paved, wheelchair-accessible trail.

The seawater playground of gilded-era San Francisco burned to the ground in 1966.

Beneath the southern end of the Golden Gate Bridge is the “Gibraltar of the West Coast,” a fort built to protect the San Francisco Bay from naval attack.

Guns that have been defending San Francisco since 1904.

Concrete strongholds stand guard over the Golden Gate.

This abandoned boat was left in place thanks to its rotting beauty.

A raised boardwalk winds through a thicket of stunted, century-old trees no more than nine feet tall.

A trash dump made beautiful by nature's power.

This massive redwood tree has a hole in the base big enough to drive through.

This ultra-modern California span is actually a titanic solar clock in disguise built by famed architect Santiago Calatrava.