One man's swirling six-acre monument of stone.

The world's largest kaleidoscope, designed by a 1960s psychedelic artist.

This abandoned factory on the Hudson River once churned out a million bricks a week.

The oldest continuously inhabited street in America.

100 massive sculptures in the Hudson River Valley.

The house that Frank Lloyd Wright "(shook) out of his sleeve at will" at the age of 86.

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

Dedicated to the art and science of glass in equal measure, this space is as much laboratory as museum.

"Gnome Chomsky" was once the largest gnome in the world, but is now simply tall for his kind.

This stone gatehouse was once the entrance to a historic mountain resort, and it had a cameo in a cheesy cult horror movie.

This abandoned cemetery is crumbling into ruin, exposing the artifacts and bodies buried there.

A winding, cliffside stretch of road overlooking the Delaware River.

The highest point in New Jersey is marked by a massive, if simply named, obelisk.

Adherence to strict Jewish laws is required to enter this ultra-conservative New York village.

Hundreds of numbered stakes hidden in the woods mark the graves of the lost souls of a nearby asylum.

This crumbling little graveyard was saved from the undergrowth by concerned veterans.

Infamous marsh filled with toxic waste, World War II-era London rubble, and dead mobsters galore.

Seven golden statues rise into the sky from sculptor Victor Victori's New Jersey front lawn.

Manhattan's Thirteenth Avenue was made on landfill then deliberately destroyed — apart from one small, obscure block.

A playground inspired by differential calculus dangles from the ceiling of the Liberty Science Center.

A vast city of the dead, where the deceased outnumber the living by more than a million.

A brooding mansion of clinker brick stands out among the Victorian houses of Pacific Heights.

A collection of memorabilia from the Beat era in the back of a San Francisco bookstore.

The oldest burial ground in the city, final resting place of city founders, Ohlone natives and murderers alike.