The longest step street in the city.

Self-sufficient greenhouse floating on the Hudson River.

A waterway covered over after the Industrial Revolution has been unearthed and cleaned up, for the enjoyment of fish and humans alike.

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

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

A beautiful, historic location open to the public.

This dilapidated castle-like structure overlooks the Hudson River at one of its widest points and was once home to nuns.

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

This fancifully decorated Victorian home in New York’s Hudson Valley is the only known fully domed octagonal residence in the United States.

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

The real-life site of Ichabod Crane's infamous gourd attack.

Oldest existing church in New York and the inspiration for Washington Irving's "The Legend of Sleepy Hollow."

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.

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

An abandoned cemetery lies in ruins as the surrounding forest swallows it whole.

America's first serial killer rests in anonymity.

One of the oldest log cabins in America is one of the last of its kind this historic Swedish dwelling remains a piece of living history.

The last of Philadelphia's wood-paved streets is now a landmark of terrible engineering.

Century-old shop, specializing in Occult products.

The corporeal remains of Napoleon III's dentist rest under this 15-story obelisk.

This sculpture of a fisherman spent six years at the bottom of the Schuylkill River.

This 15-foot tall obelisk commemorating the Philadelphia-Baltimore railroad connection sat neglected for over a century.

The singer, actor, and activist lived here during his final years, and now it’s a museum dedicated to his legacy.

The oldest active church in Pennsylvania is also the second oldest Swedish Church in the United States.