A kitschy, creepy St. Louis mainstay.

Speak to a companion on the other side of the room loud and clear through this architectural anomaly.

An abandoned factory along the Mississippi coated by a giant mural.

A big museum full of little worlds.

A floating museum that was sunk by a flood and left to rot in the tides.

A creepy sculpture of a decapitated head invites viewers to see St. Louis through its empty eyes.

This is not your typical jungle gym.

Less a museum than a bizarre fantasy world created by artists and engineers.

On a small Puerto Rican island, banks of secret naval bunkers lie abandoned and filled with piles of office equipment.

This collection started by a Cornell professor once held more than 600 human brain specimens, including the one that belonged to its founder.

The library of every book lover's dreams.

In upstate New York, gorgeous waterfalls and a watermill are slowly being reclaimed by nature.

The loneliest island in New York.

A long abandoned hospital building on the outskirts of NYC.

Read between the lines of the subway map to find the hidden abandoned Civil War fort.

A masterpiece of LGBT art has been restored in what may now be the most valuable restroom in America.

Home to the infamous "Typhoid Mary" and the worst loss of life in New York's history prior to September 11, 2001.

A once grand hotel is being retaken by the wilderness it once capitalized on.

The haunting, dilapidated remains of a former poorhouse on Staten Island's Greenbelt.

Ride the subways of yesteryear.

This whimsical group of statues is a favorite of children who love to climb all over Lewis Carroll's beloved characters.

The name of this famed hospital was once a byword for the horrors of medical and psychiatric care.

The world's oldest hologram gallery and the labyrinthine laser laboratory of a holography pioneer.

The abandoned husk of a mental institution that failed to save a Jazz Age icon still sits nearly unchanged.