Surprisingly aquamarine waters fill deep lakes formed at the end of the last ice age.

An artsy hidden staircase leads to breathtaking views of San Francisco.

The old Niles Canyon Aqueduct in the San Francisco Bay Area is a bemusing and secret trail through nature for wayward travelers.

A 140-year-old castle with underground caves hidden in San Francisco.

A line of blue paint marks the route of the inaugural parade.

The winding route passes through an enclosed alleyway, two tunnels, and leads to the White House basement.

An atomic bomb-proof strongbox protects the U.S. Constitution from terrorists and thieves.

Tour the original street level of Port Angeles, buried underground in 1914.

Rustic natural hot springs in the deciduous rain forest.

A glimpse into the "Logging Capital of the World" at a time when there was far more forest and far less machinery.

A tiny red pebble marks what may be the quietest outdoor spot in the United States.

These delicate buggers are some of the rarest fossils that have bubbled up from the Tar Pits.

Where there's quartz, there must be gold. Thus is the story of the mines of Julian, and the titillating times of the Gold Rush.

Limestone caves with spectacular showcase chambers.

Ancient cliffs resembling a kilt on Scotland's second largest island emit an entrancing sound.

A Barbary Coast watering hole built into a Gold Rush shipwreck.

A motel dedicated to Southwestern nostalgia.

Fantastic collection celebrating the final send-off.

An abandoned quicksilver mining town surrounded by the Big Bend parks.

Only known mainland rookery of the threatened Stellar sea lion.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

America's Most Wanted's set resides in this tribute to the history of crime and punishment.

The story of Two Guns, Arizona could easily be described as a Shakespearian tragedy on Route 66.

The rusting remains of the largest assembled WWII fleet on the West Coast.