A medieval church built into an ancient cave.

The world's largest prehistoric copper mine had 30,000 animal bones scattered throughout the maze of passageways.

A lost cemetery stands forgotten on a hilltop, known only to the older residents of Pomeroy.

This schoolhouse for Black American children is one of the oldest remaining in southeastern Ohio.

The largest piece of cut lead crystal adorned a grave for 75 years and is now the shining star of a glass museum.

This museum sits on the site of a decommissioned military communications base.

One of the best places to see feral Colonial Spanish Mustangs in the United States.

The origin of this mechanical boy was a mystery until he revealed his maker by writing it in perfect cursive.

A stranded woman lived alone on this remote island for 18 years, inspiring the great children's novel "Island of the Blue Dolphins."

The "birthplace of insulin," where Sir Frederick Banting realized the hormone could save the lives of Type 1 diabetics.

A historic recreation of the golden age of the Erie Canal, abandoned for some time, slowly being restored.

A small town museum celebrates the history of the Ohio county that produced Annie Oakley and other famous figures.

A storybook church made from a mesmerizing medley of multi-colored stones.

After covering almost 1.5 billion acres, the survey's still not finished.

This replica of the Greek structure is in the heart of Nashville.

Its incredible collection preserves 170 years of sewing machine history.

William Smith's iconic "map that changed the world" is hidden behind a curtain in the Geological Society building.

A small church in Uppsala hides the grave of a renowned 18th-century astronomer.

This dreamy street will transport you to wintertime in Victorian England.

The world's largest fully steerable radio telescope.

A particularly creepy abandoned hospital that sparks interest for lovers of the supernatural.

Two gems of Beaux Arts architecture that have been sitting vacant for years.

Berkeley Hot Springs presents to you "the only outdoor monument to presidential bathing."

The "mysteries" of this quintessential roadside oddity were almost destroyed by neglect but were saved by fans of kitschy wonder.