This city park was once a lookout point for George Washington’s army during the Battle of Brooklyn in 1776.

A burial ground of rusting metal grave markers.

Pulled from the rubble of one of the worst modern tragedies, a steel crossbeam became a symbol of hope for New Yorkers.

This lovely little pond is named after the hundreds of soldiers' corpses that were rolled into the waters during the French-Indian War.

The last living thing to come out of the rubble after 9/11 is now a symbol of hope and resilience.

Final resting place for the Triangle Shirtwaist fire’s unidentified victims.

Revolutionary War casualties fill the only 17th century structure remaining in Manhattan.

Brooklyn's Barkaloo Cemetery is the resting place of a scant two bodies.

A plaque immortalizes the spot where the early American spy said his famous last words: "I only regret that I have but one life to lose for my country."

The gravestone of the suffragist leader attracted extra visitors during the 2016 election.

An eccentric playboy's astounding natural history collection.

A decommissioned military complex that's now a modern industrial park.

Haunted Victorian house that inspired a legendary "Ghostbusters" court ruling.

Possibly the smallest church in the world floats in the middle of a pond.

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

A strangely angled West Village home is the only monument to an explosion that took the lives of three American revolutionaries.

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

Long-forgotten artifacts give incredible insight into New York's most glamorous hotel.

A museum collection honoring the long history of the FDNY is held in a disused Manhattan fire house.

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

An old dining hall now serves up ghost stories for lusty locals.

The life of one of FDR's possible mistresses is preserved in her palatial Hudson Valley mansion.

Final resting place of two dozen New York City harbor ships.

This collection started by a Cornell professor once held more than 600 human brain specimens, including the one that belonged to its founder.