Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

A walk through the historic city center, under the streets of Seattle.

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

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

A Roman-inspired temple once controlled half of San Francisco's waters.

Neither Spanish settlers nor anyone since has been able to tell who built these strange California rock walls.

The old Niles Canyon Aqueduct in the San Francisco Bay Area is a bemusing and secret trail through nature for wayward travelers.

San Francisco Bay's ghost town.

The world's first permanently occupied mountain-top observatory continues to report on the stars.

See massive fossils that are over 200 million years old in northeastern Arizona.

The official atomic museum of the United States explores the explosive and productive history of a much maligned energy source.