New York's unstoppable progress turned this cemetery into the smallest burial ground in the city.

Monument to a forgotten NYC disaster that claimed the lives of 1,000.

Manhattan's deadly West Side railroad, which killed hundreds of New Yorkers, is remembered by this simple plaque.

Possible relics of the ancient Roman city are hidden in this restaurant's façade.

Church in Manhattan holds the bloody sock of Padre Pio, among with many other unusual relics.

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."

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

This giant boulder is sandwiched between apartment complexes in upper Manhattan.

This memorial honors thousands of enslaved Africans and their descendants who died in colonial New York.

Salute the leader of the proletariat.

A Manhattan Episcopal church with an eerie underground crypt.

An odd, ancient window that may have once been part of a brutal prison is embedded in the side of New York's Police Plaza.

Where now stands a 42-story condominium tower of marble, glass and steel was once the central market of New York’s slave trade.

Relics given to a Manhattan church to avoid seizure by the Italian government.

A former insane asylum despised by Nelly Bly and Charles Dickens is now fashionable apartments.

A curious fountain that has no water and includes Satan, a crab, and 9 giraffes.

A hidden "place of interment for gentlemen."

Historical figures from New York City's Catholic community reside in Midtown.

A crumbling hospital from the 1850s on Roosevelt Island.

A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

Hidden in Central Park's Ramble is a troublesome cave buried just beneath the surface.

This lower Manhattan bar is set up in an old bank vault that rests beneath a skyscraper that hides even more historic splendor.

The walls are decorated with whimsical murals painted by the creator of the Madeline franchise.

A celebration of capitalism in Midtown.