These artificial caves crafted by ancient Romans were elaborate fish farms for moray eels.

One of the world's tallest, oldest, and most disgusting chocolate cascades.

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

These old stone ruins in the Oregon wilderness were once bathrooms and are steeped in legends of murder.

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

These beautiful ruins deep in the Pennsylvania woods are thought to have been a ski lodge or a speakeasy, but no one really knows.

World's first "penitentiary," meant to be humane, drove men insane.

This English-inspired Maryland garden is home to acres of opulent plant life including bushes shaped into an entire fox hunt.

The ruins of this long-abandoned unsuccessful gold mine can still be found.

An intricately designed junk art house with four extravagant junk art cars hidden in the suburbs.

The land is home to swimming ponies and a legendary 18th-century treasure.

A local farm's collection of unusual structures from a now defunct storybook amusement park.

An astounding collection of medical specimens, including bits of President Lincoln.

An abandoned stretch of highway, deteriorating next to the operational one.

An indoor miniature village and labor of love for Laurence Geiringer, a model railroad enthusiast.

This huge, disused viaduct is now a crumbling concrete underworld of covered in years of graffiti.

This abandoned Poconos resort is haunted by a history of kitschy romance and a violent fugitive.

A modern ghost town whose inhabitants were driven away by the growth of nuclear power.

The graffitied ruins stand hidden within the Pennsylvania woods.

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

No one knows who painted this mysterious mural in a Penn State basement.

Steepest flood safety railway in the entire world.