Along the Outback Scenic Byway, adjacent to hot springs, this human-made geothermal feature takes unexplained breaks.

An outsider art duo's yard has been turned into a whimsical public gallery.

A dwindling menagerie of anthropomorphic oil derrick animals still dot the barren California landscape.

A B-17 bomber stands as a memorial to the residents of Tulare County who served in World War II.

Colorado's only active volcano last erupted around 4,000 years ago.

These modest Midwestern formations are kin to Niagara Falls' impressive cliffs, more than 600 miles away.

One of only five observatories in the world built to measure the Earth's wobble.

A tunnel that brings more than a century of history to life from the deepest parts of the Niagara Gorge.

The first motion picture theater in southern Utah, reimagined and renovated as an arts hub.

A few dilapidated structures are all that remain of this deserted former silver mining town.

This highest peak in Idaho can only be reached by traversing a formation known as "Chicken-Out Ridge."

These century-old beehive-shaped kilns were built to produce charcoal for nearby mines.

A mountain range on an active U.S. Navy base hides thousands of mysterious prehistoric rock carvings.

Concrete strongholds stand guard over the Golden Gate.

Underneath this water pump, Annie Sullivan helped Keller speak her first words.

One of the few remaining carousels built by master amusement park carver Charles I.D. Looff.

The helicopter that "Tricky Dick" absconded from the White House in on his last day in office.

This Rocky Mountain mansion was the luxurious home of the authoritarian leader of a company town.

A huge work of Burning Man-inspired outsider art on the grounds of a California winery.

The fossilized remains of ancient California redwoods.

California's own majestic geyser is powered by a subterranean volcano.

The most isolated mailbox in America lets desert travelers record their passing.

A wondrous place to watch a special flower bloom.

Although built to generate electricity for Marylanders, this dam has become an all-you-can-eat buffet for American bald eagles.