Hidden in plain sight on a pair of Manhattan subway tunnels are a pair of public instruments that sing to each other.

This unmarked and unloved Manhattan subway grate created one of the most iconic images in American cinema.

One of the last few places in Manhattan that employed a pneumatic systemic keeps it on display.

An unassuming secret door once led to a legendary watering hole.

A dark patch of the ceiling at Grand Central Terminal which was not restored is still stained brown by tobacco.

New York's oldest magic store.

A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

A whimsical sensor instrument for Minneapolitans to play on their walks to work.

35,000 grape hyacinths flow like water down a garden hill.

The best place in New York to pick up the controversial, notoriously foul-smelling Asian "king of fruits."

A stone arch leads to a cavernous 1930s spring house tucked away in the Pennsylvania woods.

This spectacular public market has got meat, fish, vegetables, baked goods, and enough kielbasa for a lifetime.

An abandoned theme park with a strange and tumultuous past.

An unrecognized nation-state created in the 1820s to avoid taxes.

100 years later, they're still down there.

This bug-eyed water wheel uses the power of the Sun to clean up Baltimore Harbor.

The pits used to load the nuclear bombs onto the aircraft that dropped them over Hiroshima and Nagasaki at the end of World War II.

One of the largest-ever mental hospitals now sits abandoned, surrounded by 25,000 unmarked graves.

The place where the great marine explorer first learned to work underwater is not where you'd expect.

America's oldest Eastern European synagogue provided the immigrants of crowded Lower East Side tenements a space of sanctuary.

Marie told fortunes from her small stand on the Boardwalk for decades, including to a young Bruce Springsteen who would busk outside her booth.

Bloodstains can still be seen in this medieval church where two medics saved lives on D-Day.

A kaleidoscopic warehouse-maze of handmade neon signs.

A stranded woman lived alone on this remote island for 18 years, inspiring the great children's novel "Island of the Blue Dolphins."