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

The 80-foot tire that looms over Michigan's I-94 was once a Ferris wheel in the New York World Fair.

Chicago's largest cemetery is full of beautiful Victorian monuments and more than a few ghost stories.

Once one of the world's great cities, Cahokia was a place of religious worship, trade and mass human sacrifice before being mysteriously abandoned.

This spot in St. Louis, marked with a simple sign, has seen more pro baseball than just about anywhere else in the world.

A collection of more than 10,000 racist objects that teaches the atrocities of social injustice and intolerance in American history.

According to the legend, this strikingly beautiful hill has miraculous healing powers.

A wonderfully curated used bookstore in an airport.

This storied music venue was once a tavern that housed an Italian Anarchist book club and prohibition parties; today it's a community space for artists and musicians.

What appears to be a wizard's lair in Milwaukee actually houses a massive water pipe.

A group of artists transformed this desolate city alleyway into an outdoor gallery of street art.

The famous author's birthplace is preserved in a town that he once described as narrow-minded.

A plaque marks a former safe house on the secret route, now hidden next to a McDonald's.

The young Black revolutionary was killed before getting to see a non-segregated pool in his hometown.

The red brick house where the father of rock 'n' roll wrote some of his classic hits.

A plaque on the side of a parking garage marks the burial place of a great Ottawa chief.

One of few surviving standpipe water towers in the U.S.

This is not your typical jungle gym.

A 30-foot man on a penny-farthing bicycle rides along the banks of the Mississippi.

These ancient ritual mounds are our best window into the culture of the ancient Mississippians.

In this case, 'zero' marks the spot where the iconic Old Spanish Trail ends.

Must form and function forever remain at odds? Not if the Florida Department of Transportation has its way.

This giant iron playfully pays tribute to an early 20th-century architectural trend.

Perhaps the oldest vine in North America, this sprawling plant helps make a sweet wine.