Manhattan’s Battery Park has a whimsical carousel full of spinning, glowing fish.

A Pythagorean funhouse that tries, successfully, to prove that math is the coolest thing ever.

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

Three-story slide through the New Museum.

For over 30 years the walls of this Harlem schoolyard have been a gallery of street art by "Kings and better."

A partially hidden wall graffitied by spectators of the 1976 Bicentennial, recently rediscovered.

A tunnel once abandoned now thrives with graffiti art as an off-limits makeshift gallery.

The saddest little diner in New York.

This narrow shop in the East Village hosts a matchmaking service for the new millennium.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

Garden dedicated to native carnivorous plants and site of huge flytrap heist.

La Monte Young and Marian Zazeela's "Dream House" will immerse you in an ever changing world of sound and light.

World's first "penitentiary," meant to be humane, drove men insane.

One of the world's largest model railroads is a mind-boggling achievement.

This empty Victorian manse on Staten Island is said to be haunted but is actually a real life crime scene.

One man's lifelong obsession with death.

A storefront museum in Asbury Park honoring the Jersey Shore’s deep history of mystery—including the Jersey Devil.

These tourist trap caverns are said to be the former home of a legendary Pennsylvania Hermit.

A bunker "with enough U.S. currency to replenish the cash supply east of the Mississippi" in the event of nuclear war now protects nitrate film.

Hellam Township is reputed to feature seven remote gates, which when passed through in the right order, open an entrance to hell.

Outsider art meets paleontology at this roadside reptile repository.

Collecting 700 years of mechanical death-dealing, the NRA's sprawling gun museum is a revealing testament to the American obsession with armament.

The semi-reclaimed ruins of this canal were once part of an ambitious plan to reroute the mighty potomac.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.