Oldest existing wire suspension bridge in the United States.

Marvel at this turn-of-the-century masterpiece that has been turned into a rather stately supermarket.

The angel of death appears to weep black tears at this grave marker.

Sail through this subterranean show cave that is home to a legend that would go on to name nearly everything around it.

This lush forest valley was once mined for lumber to the extent that it was once nicknamed "The Pennsylvania Desert."

"Dark Sky Park" is heaven on Earth for astronomers, one of the rare U.S. locations with no artificial light pollution.

When the Austin Dam failed it destroyed much of Austin...and then it failed again.

Steepest flood safety railway in the entire world.

This abandoned dream castle and its cemetery look out over the city that once inspired their creation.

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

This Pennsylvania cave holds evidence of the oldest known inhabitants of North America.

These disused steel furnaces are now haunting ruins that may one day be a national park.

One of the steepest streets in the United States makes an intriguing challenge for cyclists.

The only way to see Pittsburgh is from the top of this lookout point, just like the ancient members of the native peoples did.

Take a drunken tour inside the world's largest known geode.

This railway-turned-greenway provides a pedestrian link in downtown Detroit and celebrates urban artwork.

The mysterious wonder of an underground waterfall is illuminated by multicolored lights.

Defying all odds, this lonely little tree found a home on a log sticking out of a Canadian lake.

Remains of a historic fountain that was mysteriously lost in the demolition of a D.C. traffic circle.

A pre-Industrial Age iron furnace and the site of a nearly-forgotten piece of Black history.

Wild lights and sound effects turn a walk through some caves into an eye-popping 1960s tourist attraction.

Once connected to the outside world by a single train track, this ghost town is looked after by the National Park Service.

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

This old cement mine has been used as everything from a mushroom farm to a recording studio.