Color-coded signs direct drivers on a network of routes designed to avoid Pittsburgh traffic.

Frank Lloyd Wright’s most iconic home dangles over a Pennsylvania waterfall.

The house that Frank Lloyd Wright "(shook) out of his sleeve at will" at the age of 86.

There aren't too many operational funiculars around, but Pittsburgh has two!

The United States’s oldest funicular railway glides up and down a steep Pittsburgh street.

The largest clock face in the United States is twice the size of Big Ben and infinitely more ad-sponsored.

Constructed from the ruins of a former glass factory, this park incorporates the old with the new.

Ghost stories surrounded this “castle,” the only structure from a huge mansion that was never built.

The largest ancient burial mound in Ohio.

What is it about mushrooms that makes people wish they lived inside of them?

This humble star-gazing center touts itself as the "Birthplace of American Astronomy."

After a water tower painting was accused of being an ad, a simple fix was made that gave the city a motto.

One of Cincinnati's greatest fighters once trained at a now defunct gym in this Over-The-Rhine neighborhood.

Where beautiful signs live on forever.

Bison, America's national mammal, are staging a slow comeback in Ohio's prairie parkland.

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

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

What may be America's largest classic video game arcade lurks inconspicuously in a Chicago suburb.

A flamboyantly decorated bridge signals diversity and fellowship at the entry to Indianapolis' Broad Ripple Village.

This unassuming passageway played a key role in one of the most important events in U.S. history.

A muscular Art Deco monument represents the struggle between regulators and unbridled markets.

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

Corn-inthian columns with a uniquely American take on neoclassical architecture.

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.