An acoustic anomaly with a mysterious cause sits in the heart of Tulsa.

The curiosities and wonders of pharmacy in a delightful historic building.

The world's longest known cave system.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

A heavenly experience, right here on Terra Firma.

A beautiful geyser under environmental threat.

The first declared National Monument in the United States.

Giant Redwood-themed cafeteria operates under the golden rule, "Dine Free Unless Delighted."

High on a hill overlooking Los Angeles lives a world famous, high-power conical Tesla Coil.

The now-abandoned tunnels were built for the transcontinental railroad on the route where the first wagon train entered California.

The granite monument is engraved with the image of the talking horse's head coming through a barn door.

The little-known final resting place of one of America's greatest writers.

Dozens upon dozens of boulders engraved with scripture tell the story of one man's troubled life.

Stroll through a wonderland of stupendous moss-covered trees.

I Street Bridge is the heaviest swinging center bridge in the United States.

A mysterious dark-skinned Christ statue has been this town's religious center for centuries.

A vintage video game wonderland in downtown Reykjavik.

One woman's lifelong collection is on display in this unassuming house on an Icelandic fjord.

This verdant, tree-lined Reykjavik graveyard is both enchanting and eerie.

Iceland's tribute to its thankless civil servants.

A charmingly eccentric magma chaser presents his complete history of the island's eruptions since 1947, in cinematic form, just for you.

The picturesque birthplace of Icelandic democracy is drenched in the blood of its brutal past.

This stunning concert hall has become a symbol of Iceland's national recovery.

A sulfuric martian landscape that looks far better than it smells.