A mountaintop space observatory that is certified dark.

The scuba diving training facility was named for the steam that rises from the cave's chimney.

Tokyo’s only Vaudeville-cuckoo clock–steampunk-Victorian curio cabinet time piece.

The largest self-built castle in the U.S., six decades in the making.

Florida might be at its most surreal in this museum devoted to the famed Spanish artist.

A stunning, two-tiered waterfall made famous by poets, artists and the legend of a ghost dog.

The world's longest known cave system.

A submerged archeological park still holds the wonders of a Roman Sodom.

This abandoned asylum was once a state of the art facility before devolving into one of the most deadly mental institutions in American history.

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

A hand-built folk art installation covered with messages of God's love.

Possibly the most beautiful carillon in the world, set atop Iron Mountain in Florida.

This abandoned amusement park was built on a site with a dark history.

The deepest lake in the United States, and once the site of epic destruction that lives on in legends.

A one-of-a-kind collection of a unique medium.

The United States Capitol's former columns still stand.

The feral felines of Roosevelt Island have a small army of allies and an abandoned hospital all to themselves.

This airfield is home to a number of retired vintage planes in various states of disrepair.

Hidden amid a collection of trails is the site of a tragic crash.

From failed port town to Civil War fort, the ruins of this former defense saw their finest day in the television age.

This winding road of 318 curves is a must-visit for (careful) motorcycle and sports car enthusiasts.

A historic dam made famous for its turbines and feature in a Hollywood classic.

This stunning home looks like it belongs in medieval Europe, not North Carolina.

A forgotten sea village stands silent after hurricanes deemed it obsolete.