These molds for fiberglass statues have formed an eerie, accidental sculpture park.

A tunnel once abandoned now thrives with graffiti art as an off-limits makeshift gallery.

One of the largest public housing complexes in New York once visited by Eleanor Roosevelt.

Try not to get slimed in Tribeca.

An unconventional space for art and science housed in a massive old warehouse.

Elevated freight railway turned wildly successful urban park.

Once a popular watering hole among longshoremen and shipyard workers, this neighborhood treasure spans more than 100 years of Red Hook history.

Four cars from the old system were once on display, but were removed in 2014.

Lehigh Valley barge No. 79 still gets tugged along - but now it houses a museum and unusual performances.

Lie in a hammock where George Washington stood.

Empty, but not abandoned, this cavernous Brooklyn loading dock was once considered the largest individual building in the world.

In its day this historic fort held 100 cannons pointed in almost every direction to protect New York.

Once America's longest-manned military fort, now an abandoned hulk.

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

This once luxurious Catskills resort is now a haunting ruin.

Dilapidated Mayan-themed ballroom was one of Detroit's most popular venues through the 40s.

Advice-columnist's bell tower, paid for with pennies.

The bones of an old zoo crumbling in the shadow of a new one.

The concrete shell of an industry giant remains as a playground for graffiti artists, auto scrappers, and paintball warriors.

One man's attempt to create an artistic wonder on a run-down block in Detroit.

A wacky two-story folk-art assemblage of carved and found objects, with lights, motion, and sound now in need of financial support.

Detroit housing collective working to create an "environment for revolutionary change."

Once a bastion of its community, this gothic cathedral now stands as a haunting ruin.

A Beaux-Arts triumph rises from decades of decay to become the heart of a new innovation district.