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

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

An architect's childhood fantasy treehouse made real.

A beautiful geyser under environmental threat.

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

Few other hotels can rival the grandeur of the Castle in the Rockies.

Shakespeare has been brought to life in this open air theater for the better part of a century.

Only known mainland rookery of the threatened Stellar sea lion.

City Council meetings still happen in this historic building, impeccably preserved on the inside.

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

Nuclear reactor created the plutonium used on Nagasaki.

A stunning landscape of bunkers that once stored chemical weapons.

This former coal gasification plant found a curious second life as a popular public park.

The highest point in Washington state is a volcano covered in glaciers.

The first North American landing spot for James Cook on his third voyage of discovery in the Pacific.

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

The lush coastal city of Astoria is riddled with forgotten secret sidewalks.

Where Nor'easters go to die.

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

The longest continuous lava tube in the continental U.S. offers 2.5 miles of dark explorations for the adventurous.

The largest wooden building in the world now houses a fascinating collection of aircraft.

An extraordinary mixture of natural beauty and man-made phenomena.

This charmingly homemade amusement park has been growing for 40 years.

This extravagant Art Nouveau rest stop features a million-dollar view of the Columbia River.