The enormous 250-room Vanderbilt mansion conceals hidden doors and secret passageways.

Crumbling ruins mark the site of a couple's grisly murder in the woods.

This Tennessee manse was built so opulent that the very utilities doomed it to fail.

Disney's abandoned animal island is now an overgrown ruin that was almost the coolest attraction ever.

One of the largest-ever mental hospitals now sits abandoned, surrounded by 25,000 unmarked graves.

This recently rediscovered Civil War-era submarine was the first to ever sink an enemy ship.

A former mental hospital founded in the 1930s by a eugenicist who advocated for the forced sterilization of patients.

The cruel trial of a 13-year-old boy inspired the creation of this now abandoned reformatory.

Charleston's historic city jail once held everyone from pirates to Civil War POWs.

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

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

An FDR-era tuberculosis sanatorium has stood abandoned in the suburbs of the U.S. capital for over 30 years.

A blank headstone topped with a pile of pennies marks the final resting place of the infamous assassin.

The final resting place of the tragic king and queen of the Jazz Age is tucked away in a small Maryland graveyard.

A girls' boarding school inspired by the Chicago World's Fair, once abandoned, now restored to strange and scenic glory.

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

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

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

Remnants of a storybook amusement park hidden behind a strip mall.