Only known mainland rookery of the threatened Stellar sea lion.

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

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

A dramatic, 360-degree recreation of Pickett's Charge in the Civil War.

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

The last physical evidence of the Lewis and Clark trail is one of their autographs etched into this giant rock.

One small town in the Pacific Northwest transformed itself into a Bavarian-themed tourist destination.

An obscure waterfall that looks like something out of a fantasy novel.

Site of the greatest known waterfall that ever existed.

A sleepy little town that had the greatest landslide in North American history fall on it.

The only road through the heart of Glacier National Park.

100-year-old shipwreck you can walk up to at low tide.

A Roman-style column in Oregon hides a spiral staircase inside.

A true roadside icon standing on the same plains that the herds once roamed.

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

The granddaddy of all tourist traps, built on ice water, jackalopes, and a giant dinosaur.

The first declared National Monument in the United States.

One of America's first dinosaur parks gives a window into Depression-era paleontology.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

Modeled after a famous church in Vienna, Austria—but in Helena, Montana.

A smoke stack so large, the Washington Monument could fit inside!

New fungal and bacterial species call this deadly lake home.

Native Americans built this circle of stones, which was used to predict astronomical events.

An entire town preserved as a historic landmark.