The "Seinfeld" diner.

This speakeasy continues the Prohibition-era legacy of Harlem's jazzy Swing Street.

The phone booths of New York City have all but disappeared, but their remains were once found in this "graveyard," sadly now removed as well.

The loneliest island in New York.

The oldest house in Manhattan is now a museum that remembers the home's sordid history of scandals, vice-presidents, and ghosts.

A discreet little stairway on St. Nicholas Avenue leads to a quaint and unexpected cobblestone street of 19th century wooden rowhouses.

The famous author's cottage hideaway.

This Dutch Colonial home is the oldest remaining farmhouse in Manhattan.

Along the Palisades skyline are the ruins of a large mansion built in 1911 and demolished in the 1930s.

America's greatest forgotten garden and the former stomping grounds of Son of Sam.

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.

An abandoned horticulture institute gloomily presides over rows of derelict and vine-wrought greenhouses.

A whimsical monument deep in this park commemorates the groups that helped build it.

One of the earliest bowling lanes in the U.S. doubled as a sewing school during a time when women had little job opportunity.

These World War I shooting range tunnels are now haunted halls of underground graffiti accessed through the roots of a tree.

An abandoned asylum where patients have been forgotten but their possessions remain.

A Saint Nicholas-themed ghost town in the Mojave desert.

Once in a state of dilapidation, this candy-inspired fortress is now being revived.

This derelict building used to house infirm Freemasons, their widows, and orphans.

A religious-themed park filled with folk art to bring biblical stories to life that fell into disrepair and now being restored.

These mouldering mansion ruins remember a time when the Catskills were nothing but luxury.

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

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

For over 80 years, Mayan ruins stood proudly in a most unlikely location.