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

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.

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

A technicolor place of worship for Elevationists.

The sign at the garden gate reads: "These Plants Can Kill."

Here, at the "world's longest art gallery," you'll find forty miles of ancient petroglyphs and pictographs.

A tiny theater hidden in an alley plays a constant stream of short silent films for anyone willing to peer through the peephole.

This futuristic German spa allows visitors to float in a pool of salt water while zoning out to underwater techno.

A winding path built in secret on the edge of the continent.

Hot springs monkey spa in the middle of Hell's Valley.

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

The only swimming pool listed on the National Register of Historic Places is emptied and refilled each day with naturally filtered water.

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

A collection of oddities including Dr. Kevorkian's suicide device, the Thanatron.

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

Under the right circumstances, this waterfall in Yosemite briefly turns a luminescent fiery orange.

For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

The world's only museum devoted to the wonders of fluorescence.

The installation’s official name, “You Who Are Getting Obliterated in the Dancing Swarm of Fireflies,” says it all.

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

An enormous, inside-out glass globe built in 1935.

Dramatic river bend surrounds a natural red-rocked pedestal.

An emerald-green grotto just a short trip from Austin.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.