To find the "unicorns of the deep" you've got to go downstairs.

These pretty kitties killed and ate as many as 135 railway workers.

This awkward aquarium sculpture is one of the strangest statues in Chicago.

Illegal drag racing two stories beneath Chicago’s streets.

A curious collection of miniatures in a quiet corner of the Chicago Children's Museum.

Chicago's Navy Pier on Lake Michigan was a training hub for aircraft carrier pilots during WWII.

A bronze plaque at an intersection in Hoboken marks the place where the game of baseball first took shape.

Red frames showcase remnants of one of New York's original subway stations.

Unrepaired walls from a 1920 anarchist bomb attack.

Plot your trip through the city on the sidewalk.

The oldest living tree in Manhattan comes shrouded in sinister legend.

This monument to a veteran of the Mexican-American War is one of only two in Manhattan that serve as an actual mausoleum.

Spinning silently in the lobby of an Art Deco masterwork is a massive vintage model of the Earth.

Manhattan's deadly West Side railroad, which killed hundreds of New Yorkers, is remembered by this simple plaque.

Twenty-three trees, each paired with a basalt stone, line a street in Chelsea, continuing an urban project started by German Fluxus artist Joseph Beuys.

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

Commemorating the spot where the famous scientist fed his pigeons.

This translucent sculpture represents a quintessential component of New York City's skyline.

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

100 massive sculptures in the Hudson River Valley.

This exemplar of modernist architecture is meant to captivate and inspire students of the Cooper Union.

Not to be confused with the iconic New York City skyscraper, this Chicago building is a vibrant hub for artists.

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

A display of magnificent stained glass windows is the first exhibit of its kind.