This head-spinningly bizarre Depression-era art cave is wall-to-wall quartz and Jesus.

More than five miles of underground passageways.

Visit this playground of waterfalls, caves and sinkholes.

Wild lights and sound effects turn a walk through some caves into an eye-popping 1960s tourist attraction.

Enormous lake at the bottom of a unique cave system.

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

After the parade, students throw their beads on the tree hoping for good luck on exams.

Site of a former hidden treehouse in New Orleans.

This macabre shop, filled with art, oddities, and taxidermy is hidden in the heart of the French Quarter.

The world’s largest underground marble quarry is hiding in Vermont.

This cavernous abandoned marble mine is popular with ice skaters in the winter.

Around half a million years ago, these magnificent columnar basalt cliffs were formed from cooling lava.

A century-old cabin off of Highway 30 touts an unusual construction material: dinosaur bones.

One of the smallest towns in the United States.

The only natural lake in the world that drains into both the Atlantic and Pacific Oceans.

This Yellowstone geyser may not shoot as high as the nearby Old Faithful, but it erupts for considerably longer.

Devilish landscape, once cinema home to giant alien bugs, now derelict roadside attraction.

An architect's childhood fantasy treehouse made real.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

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

A beautiful geyser under environmental threat.

The first declared National Monument in the United States.

Three generations of intrepid collectors display their curious artifacts in a homemade museum right next to the caves they discovered.

A chance to sleep among the firs and pines of the Oregon forest.