These enduring murals depicting a distinctly Marxist tribute to capitalism could not even be defeated by McCarthyism.

To truly appreciate Detroit's landmark skyscraper, you have to step inside.

Controversial tribute to the heavyweight champion boxer who grew up in Detroit.

Inspired by a piece of concrete, these three pyramid-shaped buildings have been beloved Indianapolis landmarks for over 50 years.

You can walk through the first Boeing Air Force One, which famously carried JFK's casket from Dallas back to D.C.

Inside houses a vast collection of military aircraft and missiles spanning the ages.

Sail through this subterranean show cave that is home to a legend that would go on to name nearly everything around it.

The souvenir got the company’s founder out of a pretty pickle at the World’s Fair.

Found art has transformed this Pittsburgh neighborhood into a psychedelic dream.

This permanent exhibition celebrates the finest of our heartless automatons both real and fictional.

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

A favorite of Amelia Earhart, ranking among those rare bridges that can be crossed without changing sides of the river.

A giant lumpy candle serves as a beacon for this highly scented pit stop.

The remains of Martha, the last known passenger pigeon, serve as a tool to educate about conservation.

This lovely picnic spot featuring thunderous jet landings is an aircraft spotter’s dream.

The romance of early commercial flight still fills this Art Deco destination.

An astounding collection of medical specimens, including bits of President Lincoln.

Brain collection and database that narrows the gap between man and animal.

Known as "Toronto's Flatiron."

This whimsical fountain pays tribute to Toronto's four-legged friends.

The artwork commemorates the many ways 20th-century people perished while on the clock.

Secret Swing.

One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

One of Canada's most incredible rare book collections holds hundreds of thousands of gorgeous tomes that the general public can touch.