This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

This region of Slovakia boasts some of the most plentiful opal mines in the world.

America's only nuclear missile silo open to the public.

Eons ago, a rushing lava river formed this pristine passage through solid rock.

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

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

The mysterious wonder of an underground waterfall is illuminated by multicolored lights.

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

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

The world's longest known cave system.

This natural wonder drops 16 stories straight down through rare flora and streaming waterfalls.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

Seemingly grown on some other world, these New Mexico rock formations look like a disused science fiction set.

Crypt mausoleum in cathedral's basement contains relics of third century Roman martyr, Saint Vibiana.

A beautiful geyser under environmental threat.

The hike through a narrow river flanked by the 2,000-foot-tall walls of Zion Canyon is one of the best in the world.

This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

The land is full of geologic eye candy, such as otherworldly spires, mushroom-shaped hoodoos, and prehistoric fossils.

For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

The legendary building that needed ghostly approval before being built.

The installation’s official name, “You Who Are Getting Obliterated in the Dancing Swarm of Fireflies,” says it all.

James Turrell's total color immersion art installation, hidden on the top floor of a luxury handbag shop.