The mummified relics of an American missionary.

Cryptic messages embedded in the New York City sidewalk.

The New York hotel where tragic visionary Nikola Tesla spent his final hours, destitute and alone but for the pigeons.

Have a steam and some blini at this cafe in a century-old bathhouse.

An annual extravaganza of Broadway theater memorabilia.

This subterranean oyster house has been the pearl of Grand Central Station since 1913.

Prove you deserve to be fed by Kenny Shopsin.

New York City's smallest piece of private property.

A dilapidated dock tells the story of Titanic's missed arrival.

A blank headstone topped with a pile of pennies marks the final resting place of the infamous assassin.

“Invented in Key West, Perfected in Brooklyn."

Tucked in a nondescript downtown Brooklyn mall is a bar containing a remarkable turn of the century anatomical wax collection last seen in 1920s Berlin.

This cemetery has graves dating back to the 17th century, including the city's oldest carved tombstone and an ominous cryptogram.

This beautiful building in the heart of Manhattan's Financial District was empty for decades.

One man’s religious convictions led him to build this stone castle meant to withstand an apocalypse.

The oldest known metal-mining site in England dates back to the Bronze Age.

This Manchester laundromat is hiding something.

What do we know about the real woman behind one of the Beatles' most famous songs?

John Hendrix predicted the creation of the "Secret City" built as part of the Manhattan Project.

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

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

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

A hands-on traveling collection of the innovative devices of yesteryear.

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