The former estate of the Guggenheims, part of the opulent Gold Coast that inspired the Great Gatsby.

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

Spies, love letters, and ghost stories have all left their mark on this home-cum-museum.

This delicate museum is devoted to the art and industry that once supported Cape Cod's oldest town.

35,000 grape hyacinths flow like water down a garden hill.

The home of one of America's most wealthy industrialists is now a historic site that remembers a more decadent time in the country's history.

Decades after testing the polio vaccine on unwitting patients, this historic mental hospital sits in ruin.

A millionaire's abandoned swimming pool from the gilded age of one of America's most distinguished families.

Beneath the mossy overgrowth covering this once-sprawling campus lies decades of history and the secrets that come with it.

Reclaimed by nature, the ruins of Doodletown, New York are remnants of a town consumed by a state park.

Forgotten under the construction of a new urban roadway is a small, abandoned part of town.

Reforestation in action is the main attraction in this abandoned quarry.

A ruined mansion hidden in the woods of the Hudson Valley, home of a tragically doomed romance.

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

The abandoned husk of a mental institution that failed to save a Jazz Age icon still sits nearly unchanged.

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

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

Two distinctive homes on a New England village green look like a couple of frosted wedding cakes.

The world's best collection to gauge whether or not you should wear a scarf outside.

3,200-square-foot mural inside Dartmouth Library depicts the history of America with images of human sacrifice, ancient gods, and other unspeakable terrors.

Protecting the future of some of the rarest and most misunderstood mammals of North America.

The first evidence of some of the Earth's earliest life was found in this fossilized undersea grotto.

An abandoned 19th century quarry in the middle of the woods, remade by unnamed wanderers into a massive series of rock thrones.

Tucked away on the second floor of a small town library is one of the great private Victorian taxidermy collections looking today very much like it did in 1909.