This sacred cavern, 400 feet deep, is home to millions of bats and an ancient burial ground.

Labor provided by Great Depression-era programs restored these 25,000 acres in Tennessee.

Back in 1952, you could get a mushroom cloud chaser with your atomic cocktail.

A Prada store in the West Texas desert that is never open for business.

The universally beloved children's television figure is interred on a high hilltop in one of western Pennsylvania's oldest cemeteries.

Once a menacing challenge for trailblazers, this trail is now the most scenic drive in Utah.

148 feet long and in the middle of a verdant forest.

The now-abandoned tunnels were built for the transcontinental railroad on the route where the first wagon train entered California.

The hotel where Martin Luther King Jr. was shot is now a museum dedicated to his work.

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

Earth's tallest volcano is sacred to Native Hawaiians, and home to a dozen world-class observatories.

An optical illusion found amid a logged redwood forest.

Visitors can walk over the largest concentration of Columbian mammoths to have died from one event.

This head-spinningly bizarre Depression-era art cave is wall-to-wall quartz and Jesus.

A mysterious light floating in the trees of Arkansas may be a piezoelectric effect.

A motel dedicated to Southwestern nostalgia.

A ship that lived many lives under many names is now known merely as the "Ghost Ship."

This narrow canyon has been carved by the river over thousands of years into spectacular and curious forms.

A new kind of theme park for adults off the Las Vegas Strip.

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

This turn of the century masterpiece has a mysterious goaty interloper.

A luxurious 1880s hotel with its fair share of Tiffany stained glass, Edison electricity, and of course, ghosts.

A cave's rare beauty held a cavernous secret hidden underground.

This concert pavilion on the shore of the Great Salt Lake has been destroyed by fire, water, and disinterest but keeps coming back.