Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

In a city filled with Frank Gehry buildings, one stands out as one of the architect's weirder works.

Hidden in plain sight on a pair of Manhattan subway tunnels are a pair of public instruments that sing to each other.

Abandoned bridge hidden deep in the San Gabriel Mountains.

The world of the ancient Celtic civilization explained through a bewitching 11 acre garden.

Storyville was New Orleans' historic red light district and hotbed of jazz music, sometimes referred to simply as "The District."

Now famous as the "Harry Potter bridge," this impressive concrete viaduct has long been an icon in its own right.

Walk 2,300 feet above the ground on the "Troll's Tongue."

A tiny red pebble marks what may be the quietest outdoor spot in the United States.

Sandstone rock formations that look like they belong on the cover of a progressive rock album.

Bizarre lunar-like landscape with thousands of large stone "hoodoos."

The gloomy ruins that inspired Bram Stoker to bring Dracula to life.

Experience a quartz crystal sound bath inside a storied, all-wood sound-chamber.

An inconspicuous footbridge beloved by San Diego locals.

An Oxford museum where visitors can have tea with the Mad Hatter and climb through the wardrobe to a fantasy land.

The last of its kind in the country.

Sleep snuggled in a sphere suspended atop the forest canopy of Vancouver Island.

A series of caves under Castle Hill that once held the prisoner Vlad Tepes, better known as Count Dracula.

Nondescript elevator doors open to reveal a stunning, surreal world.

A half-mile long and three stories high, this bridge over the Des Moines River Valley mimics a descent into a mine shaft.

Geothermal waterfalls in Tuscany.

The remains of the first punk club in L.A.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

A popular swimming hole that hides one of America's most deadly diving spots.