There must be a pun in this haystack somewhere...

This otherwise innocuous bodega was once the headquarters of the most feared assassin's guild in American history.

Curious crustaceans support an obelisk from ancient Egypt that now stands in modern-day Central Park.

This futuristic airport terminal was abandoned for decades before reopening as a hotel—with a vintage plane of its own parked out back.

A Manhattan courthouse hides a small but scathing memorial to Holocaust injustice.

The beautiful tunnel that ran from the lobby to Penn Station is still hidden underneath 34th Street.

Tucked away amidst some of the most famous addresses in the world is New York's only fraction of a street.

The final resting place of the great escape artist, where some still gather to wait for his escape from death.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

Nikola Tesla's former home contains an homage hidden from plain sight.

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

New York City's smallest piece of private property.

Ride the subways of yesteryear.

Erected in memory of Sir Arthur Conan Doyle, who was born close to this spot, this statue commemorates the author and his famous detective.

This ordinary-looking mailbox has a rather explosive history.

An ornate "graveyard" for some of the country's forlorn building relics.

An artist's whimsical transformation of everyday objects.

The colorful stairs are made with marble from the world's major quarries.

The tomb of one of Scotland's bloody historic villains is a magnet for bumbling desecrators.

A secret garden in a picturesque Edinburgh village has inspired artists for centuries.

A unique sculpture park that features the works of several famed artists.

The remains of the concrete ship can be seen during low tide.

This tallest folly in the world began its life as an elaborate factory chimney.

This Gothic Revival castle used as a shooting location for "The Secret Garden" and other films.