Huge abstract sculptures of the Puerto Rican Flag.

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

Home to a protest movement, a bombing, and a dramatic change in labor history.

The unluckiest U-boat in the entire German fleet is now on display in a Chicago museum.

Contrary to popular belief, this secluded statue doesn't represent Pennsylvania's founder.

South Philadelphia is home to Keith Haring's only surviving in situ collaborative public mural.

This elaborate towering structure was once famed for its revolutionary height.

One of Philadelphia's largest murals resides hidden under this bridge.

A hollow cement depiction of time's inexorable effect on the human body.

This $3 million model train takes you through Chicago, Seattle, and the thousands of miles in between.

A lush green oasis in the middle of Chicago.

A gothic church spire sits atop this skyscraper, the tallest church in the world.

A Bibliophile's Dream.

One of the last functioning antique elevators in Chicago.

Three courses accompanied by Christian rock.

This funicular railway rumbles along for a mile up the nearly vertical face of Chattanooga’s Lookout Mountain.

Follow the steps, and this roadside artwork will teach you how to dance.

Once decrepit and slated for demolition, now one of the longest pedestrian bridges in the world.

The metal spire on the roof of this tower was intended as an airship docking station, but it was never actually used.

This little-known memorial honors those who have donated their bodies to medical training.

A 56-foot tall statue of the god of fire looks out over Birmingham, Alabama.

Once one of the largest producers of pig iron in the world.

A little sculpture with a large wardrobe.

Most prolific publishing house in the 1600s open to the public.