Running under an entire mountain, the longest highway tunnel in North America is kept fresh using portal fans and jet fans.

Roadside collection of 65,000 signs.

A historic freight system that found the true gold rush is in tourism.

This decommissioned DC-3 now forever points into the oncoming wind.

Natural earth mounds formed in the far north.

This small city where almost everyone lives in the same building can only be reached via North America's longest tunnel.

Four-story concrete hotel never opened to customers.

The king of U.S. high points towers over every other peak on the continent.

Only known mainland rookery of the threatened Stellar sea lion.

A heavenly experience, right here on Terra Firma.

The deepest lake in the United States, and once the site of epic destruction that lives on in legends.

Once close to extinction, there is no shortage of elephant seals on the beaches of Año Nuevo State Park.

A New England-style lighthouse along California's beautiful Highway 1 gets a re-do.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

Concrete strongholds stand guard over the Golden Gate.

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

The longest living non-clonal organisms on Earth.

This rugged area of red rocks and arches is often considered one of the most beautiful places on Earth.

Two mammoth statues inspired by equally tall tales lure tourists to this roadside attraction.

Commonly referred to as the most photographed Victorian home in the United States.

An optical illusion found amid a logged redwood forest.

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

One of the most scenic stretches of road in America winds between some of the country's oldest trees.

Trails through lava-carved tube-caves display sparkling bacteria and a rich history.