This lake in the Cascades lives up to its name, disappearing down a hole every spring.

Eons old volcanic activity created one of the most stunning rock formations in the United States.

Found art has transformed this Pittsburgh neighborhood into a psychedelic dream.

The longest navigable underground river in the United States is home to countless blind and albino animals.

This Big Sur waterfall drops 80 feet directly into the Pacific Ocean, and inspired the hillside house up top.

A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

Sail through this subterranean show cave that is home to a legend that would go on to name nearly everything around it.

Hidden beneath a bridge, this waterfall is known for the large amounts of graffiti painted on its base.

This "zoo" is a cross between a junkyard and a sculpture garden, featuring animals you won't see anywhere else.

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

A clear blue swimming hole with hidden caves, still unexplored.

At this Denver landmark, the meals are compulsory, the sopapillas are complimentary, and the insanity is everywhere.

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

The "Seinfeld" diner.

Better known as the "Body Farm," this unique research facility has been studying how human bodies break down since the 1980s.

Tour the sci-fi-esque reality of governmental disease management.

Breathtakingly blue walls shimmer inside the "Glacier Behind the Town."

Hundreds of glow-in-the-dark objects light up a museum in a historic zinc mine.

Wild lights and sound effects turn a walk through some caves into an eye-popping 1960s tourist attraction.

This futuristically sylvan church is a glass-enclosed marvel of modern architecture.

These eerie outliers of the lightning bug family glow a mysterious blue color.

Once a mortuary that held the remains of Buffalo Bill, this Denver hotspot is now a death-fixated restaurant.

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

This grand gothic brewery has been pumping out suds for over a hundred years.