Plundered and left asunder by grave robbers, this ancient necropolis has been painstakingly pieced back together.

A mysterious pre-Incan ruin believed to have miraculous healing powers.

America's oldest archaeological site or a muddled case of wishful thinking.

These delicate ruins need more tourists to keep them from fading away.

These giant mummies are set ominously into a Peruvian cliffside and topped with real human skulls.

Neither Spanish settlers nor anyone since has been able to tell who built these strange California rock walls.

Ancient human, animal, and geometric figures drawn in the earth.

Some of the tallest ancient American ruins continue to inspire awe and curiosity.

Native Americans built this circle of stones, which was used to predict astronomical events.

The largest earthwork effigy in the world.

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

Nondescript elevator doors open to reveal a stunning, surreal world.

A museum devoted to bringing to light forgotten or neglected histories through exhibitions, education and public programming.

An illegally built ramshackle mansion tucked in the middle of Brooklyn is now being turned into condominiums.

Check out the underground party scene at the "Burning Man of Brooklyn."

This sculpture by artist Fritz Keonig survived the 9/11 attacks and now stands as a monument to the victims.

This beautiful building in the heart of Manhattan's Financial District was empty for decades.

A room in New York City that contains 250 cubic yards of dirt worth a million dollars.

La Monte Young and Marian Zazeela's "Dream House" will immerse you in an ever changing world of sound and light.

One kilometer of thick brass rod laid out before your eyes.

A dark, dank room in subterranean Manhattan was the site of a ghastly murder.

A terrific purveyor of natural history objects and curios.

A tiny museum housed in a New York freight elevator specializes in the "overlooked, dismissed, or ignored."

Tucked in the back of this amazing antique store is an important piece of medical history.