The drama of nature in full effect in this Nevada State Park.

The longest continuous lava tube in Oregon.

Abandoned concert venue legendary for its rock counterculture.

An underground magnet for ever-changing street art.

The ruins of this antebellum sugar plantation are the end result of a Seminole attack during the Florida Wars of 1836.

San Francisco's urban bison herd has persisted in the face of extinction, development, and disease.

A stone arch leads to a cavernous 1930s spring house tucked away in the Pennsylvania woods.

This rare example of a "tidefall" is a spectacular drop from the cliffs down onto the beach.

Hidden in plain sight on the Hudson River is an abandoned train station where nature has taken over.

The artist James Turrell is repurposing an extinct volcano crater as an observatory to experience the cosmos.

Once an ambitious nature spa, these forest ruins now provide a serene monument to failure.

Prehistoric animals decorate this popular outdoor park.

The Magical World of George Phar Legler.

A small flooded ghost town with a few scattered structures remaining.

The crumbling remains of a 19th century fortess.

Half of a waterfall goes into the river while the other half seems to disappear.

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

A tiny red pebble marks what may be the quietest outdoor spot in the United States.

A multi-storied adobe complex has been inhabited for more than a thousand years.

A once-booming Mississippi River town with a history of racial violence is now eerie and mostly abandoned.

The second largest waterfall by volume in the U.S., Willamette Falls is outdone only by Niagara in the amount of water that is pushed northward.

This naturally heated mountainous creek has created a group of neon blue pools of potentially deadly boiling water.

Abandoned power station once home to a squatter community, now being developed into an arts center.

These millipedes glow not out of attraction, but as a not-too-subtle warning.