A harrowing trail up a mile-high mountain.

These layered sandstone mountains in China look like they are made of pressed crayons.

Snow-capped peaks, colorful waterfalls and stunning vistas on the edge of the Himalayas.

Rock-cut caves and 7,000 Buddhist sculptures carved into the nearly sheer face of a sandstone mountain.

The internal railway of one of the biggest steel plants in America has been transformed into a linear park with unique industrial views.

The wooden octagon in which Huckleberry Finn and A Connecticut Yankee were born can still be visited in upstate New York.

A museum dedicated to the history & joys of the trail & your best chance to see hikers throwing up ice cream.

A toxic ghost town sitting atop a massive coal fire.

"Dark Sky Park" is heaven on Earth for astronomers, one of the rare U.S. locations with no artificial light pollution.

Penn State's giant bug collection.

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

A book collector's dream, this Toronto bookstore has the world's first "Biblio-Mat," a random book vending machine.

This massive solar system model is sprawled out across Maine's suburban wilderness.

Sculptures, jams, and the wild west collide at this folksy retreat.

Trinkets and toys lovingly handmade by maximum security prisoners.

Steam engines and conveyor belts are remnants of a genius system left in the middle of the Maine woods.

Former laboratory of radical psychiatrist Wilhelm Reich.

The inventor of a number of hybrid corn species is immortalized with a field of giant corn.

An abandoned 19th century quarry in the middle of the woods, remade by unnamed wanderers into a massive series of rock thrones.

Trash-filled shrines to an unofficial saint known for her endless breast milk dot the highways of Argentina.

A fantastical group of cliffside stairways, bridges, and twisting paths carved out of stone provide a surreal coastal hike.

A toxic lake near a volcanic caldera that is home to flamingos and other life.

What was once a unique system of urban elevators is turning into a mechanical ruin.

Bohemian paradise covered in majestic forests.