The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

Take a drunken tour inside the world's largest known geode.

Olfactory delights in San Francisco's Botanical Gardens.

This incredible collection of vintage pinball machines can be played at 25 cents a pop.

A beautiful geyser under environmental threat.

This naturally-sourced hot spring is now home to a clothing-optional resort.

Seemingly grown on some other world, these New Mexico rock formations look like a disused science fiction set.

The first declared National Monument in the United States.

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.

Carnivorous plants, medieval aphrodisiacs, and the largest original wood structure glass conservatory in the western hemisphere.

Relics of the 1894 Midwinter Exposition continue to delight visitors today.

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

The oldest cemetery in New Orleans, resting peacefully for over 200 years now.

Hollywood's most famous landmark, the "temporary" sign that has stood for decades longer than intended.

One man has carved a number of natural New Mexico caves into psychedelic sandstone temples.

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

A giant Troll lurks under one of Seattle's oldest bridges.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.