This abandoned prison castle has become an imposing gallery of graffiti art.

North America's oldest quarantine facility was built in response to Philadelphia's 1793 yellow fever outbreak.

This once-grand marvel of engineering is now 41 miles of scenic hiking trail.

This abandoned cemetery has a dark past of bodies buried over bodies.

Hidden in one of New York's oldest subway stations is the final remnant of the site of the bizarre Shakespeare Riots.

The wreckage of a deadly bomber plane crash can still be found near an Arizona peak.

The lush coastal city of Astoria is riddled with forgotten secret sidewalks.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

In this small Phoenix taxidermy emporium, you can find everything from a squid in a jar to a freeze-dried toad.

Largest magic museum in the United States with more than half a million pieces of memorabilia.

A park and memorial dedicated to the victims of the deadliest school massacre in American history.

Etched into a dry lake bed, this massive directional indicator is accurate without magnets.

A rural hall of justice holds the world's only comic book and superhero museum.

Almost half-way between the Equator and North Pole.

At one time this small mining village was the highest town in America but now it sits abandoned while the mine churns on.

A once crucial portion of the Long Island railroad still lays abandoned, waiting to be turned into an urban park.

An abandoned water sports stadium that has become a haven for graffiti and decay.

The ruins of a cotton mill that was burned in the Civil War are still hidden in a Georgia forest.

The ghost town left by the worst nuclear disaster of all time is being taken over by nature and urban explorers.

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

This tiny museum kept in a B&B laundry room holds the death mask of notorious bank robber Pretty Boy Floyd.

A unique attraction and museum dedicated to exploring iconic roadside structures.

Amsterdam's Red Light District leaves little to the imagination.

A time-capsule monument reminding future generations of the importance of efficient and effective use of natural resources.