Massive crater in central Oregon.

Despite its name, this route in southern Utah offers a heavenly day trip.

The largest natural travertine bridge in the world is nestled in a small canyon in central Arizona.

Gleaming self-built castle towers made from beer cans and inspired by "Vitamin Mary Jane."

The highest dunes in California are the most likely place in the area to hear the Singing Sands.

On the outskirts of a reborn ghost town, a decaying post office remembers the bad old days.

35,000 grape hyacinths flow like water down a garden hill.

This sacred cavern, 400 feet deep, is home to millions of bats and an ancient burial ground.

North Carolina's finest examples of Native American pictographs have survived for 5,000 years.

This historic stone barn is the former home of legendary cattleman Charles “Lonesome Dove” Goodnight.

This nearly abandoned town was once a thriving mining community until a series of fires.

A coal fire has been burning underground here since 1896.

Only known mainland rookery of the threatened Stellar sea lion.

The remains of the iconic train crash from the movie The Fugitive can still be found rusting along the Great Smoky Railroad.

A well-preserved Ancestral Puebloan ruin tucked beneath a desert cliff.

The world's largest mountain carving could fit all of Mount Rushmore inside it many times over.

Once thought to be the oldest living tree in the world, Methuselah was germinated before the Egyptian pyramids were built.

Ancestral Puebloan ruins, natural arches, and box canyons abound in this seldom-visited corner of Monument Valley Navajo Tribal Park.

In a 345-million-year-old cave that's 200 feet underground, dinner awaits.

Where manatees are the snowbird vacationers in these balmy Florida springs.

Manhattan’s Battery Park has a whimsical carousel full of spinning, glowing fish.

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

One of the world’s largest collections of petroglyphs records 2,000 years of human activity.

Oddly shaped rock formation, misassociated with a nearby utopian community.