This once-private estate is now a dreamy, meditative garden that's open to the public.

The remnants of two World's Fairs are here, complete with a 12-story globe, a mini-Manhattan, and a UFO-shaped pavilion.

A graffiti Mecca welcoming artists from around the world.

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

This mysterious marker puzzles pedestrians and infuriates geographers.

A Manhattan office building is home to the world's largest chess board.

A miniature rainforest is growing inside of a Midtown Manhattan office building.

Where the four original members of the Ramones hung out and revolutionized punk rock.

Unrepaired walls from a 1920 anarchist bomb attack.

A celebration of capitalism in Midtown.

Blighted Irish field and the ruins of a 19th-century cottage on the edge of urban Manhattan.

Amid the bustle and noise of the Financial District hides a secluded garden oasis above the city streets.

This Wall Street bar was once a hub of revolutionary activity where Washington famously bid farewell to his troops.

Under a glass sidewalk lie the remains of some of Manhattan's oldest buildings.

This natural rock "church" might not be a proper chapel but that doesn't mean it's not beautiful.

These conical kilns measure an impressive 30 feet in diameter, and were once used to produce charcoal for a local blast furnace.