The only diamond mine in the world where you can keep what you find.

Trails through lava-carved tube-caves display sparkling bacteria and a rich history.

A miraculous natural phenomenon known as "the spring that breathes."

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

Hot Doug's "Hot Dog" Stand.

A watering hole where the options for seating include a bar, patio, or subterranean cave.

A beautiful geyser under environmental threat.

Where beer lovers can literally immerse themselves in beer.

Old-fashioned knowledge and modern engineering create the world's only rotating boatlift.

The deepest lake in the United States, and once the site of epic destruction that lives on in legends.

Some of the clearest water anywhere in the world.

One of the best beaches in the entire world.

Millions of glowing microscopic organisms light up the waters of this luminous lagoon.

Medicinal spa created with the discharge from a geothermal energy plant.

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

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

A island reachable by a causeway at low tide is possibly one of the earliest Western European locations to be identified in text.

Northern Ireland's Brobdingnagian stepping stones.

A cave's rare beauty held a cavernous secret hidden underground.

Handcrafted thermal spa washes away each night with the tide.

The unique waterfall in Iceland's south features a backdrop of geometric black lava columns.

The mysterious round rocks of Schooner Gulch.

This huge pile of volcanic boulders hides a stunning network of secret grottoes.

The ancient past meets the retro-future at these dinosaur tracks that are protected by a geodesic dome.