Civil War-era Fort designed to withstand invasion and attack, with tricky traps called "murder holes."

An enormous, inside-out glass globe built in 1935.

The Mysterious Witch Bonney, a haunted statue in an old industrial city.

A beautiful Victorian-era cemetery, complete with a miniature village.

Radical Bookstore and Community Space.

The loneliest island in New York.

All that remains of a magnate's dream home is a historic gate and an abandoned public pool.

A long abandoned hospital building on the outskirts of NYC.

A virtually untouched "home on the hill" for the flora and fauna of Rhode Island.

A once crucial portion of the Long Island railroad still lays abandoned, waiting to be turned into an urban park.

Unique antiquarian shop specializing in globes, maps, and prints.

Read between the lines of the subway map to find the hidden abandoned Civil War fort.

A New York garbage depot holds a secret collection of weird and wonderful refuse.

This ruined fort hidden at the top of Central Park can't seem to keep from losing its historical plaques.

An architecturally unique lighthouse that had to be lifted up and moved to avoid falling in the sea.

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

Visit the monolithic tomb of America's most famous general.

Piano-making empire filled with 200-year-old steam machines still churning out 1,000 instruments a year.

Harlem park dedicated to compulsive hoarders killed by their own junk.

The site of a tragic massacre that spawned a multimedia franchise.

The end of the 4 Line is also the end of the line for 300,000 souls in one of NYC's most illustrious cemeteries.

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.

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