A mysterious monument meant to be a guide into "an Age of Reason" was destroyed after an apparent bombing.

Final resting place of one of the classic authors of horror literature.

A labor of love built by local hang-gliding enthusiasts, this ideal launch spot was outlawed by the authorities and has since been largely abandoned.

The first of Lancaster's "rural cemeteries."

Underground tunnels remain beneath this abandoned mental asylum.

A coastal rock outcrop with mysterious inscriptions variously attributed to Native Americans, Portuguese, Phoenicians, Norse, and more.

Visit the site of a subway powered by nothing more than air--and lots of it.

This was one of the first (and last) university-built and operated nuclear reactors.

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

Dr Barnes' $25 billion private collection of art and arboretum.

The site where Joe Gallo kept his guns, pet lion, and launched an all out mob war in 1960s Brooklyn.

A historic grist mill and active sluice on the Black River.

Daily lunch spot for many of Washington, D.C.'s cab drivers.

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

Bat house that has only ever housed bat for one night; they all flew away and never came back.

Where Greenpoint's first European settler—and troublemaker—made his home.

One of the first major shipyards in Brooklyn.

The world's second largest single-dish radio telescope, once used to contact E.T.

Tiny observatory made big contributions to the study of the Earth's motion.

Tour the dark and beloved poet's former cobwebbed basement, which may have inspired "The Black Cat."

Elevated freight railway turned wildly successful urban park.