A ghost town at the airport is now a refuge for blue butterflies.

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

A spiritual retreat in the heart of Los Angeles offers stunning gardens and a labyrinth to lose yourself in.

When ecosystems collide in the arid Southwest.

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

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

A 300-yard long natural tunnel runs through a ridge deep in the Appalachian Mountains.

The highest bridge in America was built for an almost unnervingly small amount of money.

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

A beautiful 62-acre Catholic shrine and botanical garden.

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.

The only theatre in the world constructed specifically for sound movement.

This New Orleans tree is filled with hidden chimes that produce a carefully tuned melody.

Philadelphia boasts one of the best — and most often overlooked — traditional Japanese gardens in North America.

A one-of-a-kind collection of a unique medium.

One man's homage to the sun continues to grow like a glass fractal.

Enormous lake at the bottom of a unique cave system.

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

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

A walk through the historic city center, under the streets of Seattle.

A miniature rainforest is growing inside of a Midtown Manhattan office building.

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

Under the right circumstances, this waterfall in Yosemite briefly turns a luminescent fiery orange.

Manhattan’s Battery Park has a whimsical carousel full of spinning, glowing fish.