Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

A super-sized promotional trick that is now a D.C. landmark.

A scenic fort on the harbor protected Philadelphia from an attack that never came.

The largest dune field in the Mojave offers a chance of hearing the 'singing sands.'

Michigan’s most famous shoe tree.

An unlikely beach paradise of giant sand dunes lies between two lakes just a few minutes from Michigan's cherry country.

The fifth-longest suspension bridge the world, connecting one Michigan peninsula to another.

A park and memorial dedicated to the victims of the deadliest school massacre in American history.

This national park on the shore of Lake Michigan features remarkable dunes that lie at the heart of a Chippewa legend.

Island where motor vehicles are banned -- home to the only carless highway in the United States.

This freshwater spring fills with 10,000 gallons of water per minute.

The last holdout of a pre-Civil War rebel who took the matter of slavery into his own hands.

Berkeley Springs State Park boasts the nation's only monument commemorating presidential bathing.

The remains of this hell for leather wild west town can still be found in the Arizona desert.

A pair of giant roadside arrows are all that remains of a former Route 66 trading post.

A wild west cemetery in Tombstone, Arizona, provides a window into the Old West.

The largest natural travertine bridge in the world is nestled in a small canyon in central Arizona.

A geological mystery on Camelback Mountain.

This rare triple-jurisdiction drawbridge passes through Virginia, Maryland, and Washington, D.C.

An eerie, decaying ghost town destined to fade into the forest.

The haunting "Hell House Altar" is one of the few remnants of an abandoned college that has been a magnet for local legends.

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

The only place for a truly presidential dram.

The graveyard holding the remains of George Washington's slaves was forgotten for nearly 200 years.