This natural marble cave is one of only five national monuments in Oregon.

A volcanic fissure over two miles long and up to 70 feet deep.

A haunted hot springs hotel that went from healing retreat to asylum before it was restored.

This strange hill on Old Fort Road where gravity works in reverse has been fascinating locals for years.

Two massive rock outcroppings on the Oregon coastline.

Formerly secret, precariously perched boulders.

Despite a legend that says this highest peak in Oregon was climbed in high heels scores of people have died on its slopes.

Unknown to many, this sparkling turquoise lake hides amid Oregon's snowcapped mountains.

Massive crater in central Oregon.

The longest continuous lava tube in Oregon.

A massive sea stack famous for its appearance in The Goonies.

Oregon's unexpected high desert, displaying layers of time in a colorful show.

The eerie remnants of an ancient forest were hidden under the sand for centuries.

No one knows how this Pacific Northwest spruce tree came to have so many trunks.

Hollowed out cedar log tubs set in an ancient towering forest.

The seamy, underground secrets of Portland's criminal past.

On the Oregon coast there is a natural hole that seems to be draining the sea.

Home to a timed geyser created by complete accident.

This trail leads to a mine that was used as a sanctuary during the Great Fire of 1910.

A lava tube cooled to form this long tunnel that stays chilly even at the height of summer.

Two geologically young and nearly circular volcanic subsidence craters, each about a half-mile in diameter, abruptly break the nearly featureless Snake River Plain.

A volcanic core jutting above the plain between the Snake and Boise Rivers, a marker identifies the reference point for all U.S. Government Surveys in Idaho.

Cross the Continental Divide through an old railroad tunnel, and ride back to the top on a shuttle.

Rare and gorgeous birds abound in this protected wildlife sanctuary.