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

The concrete shell of an industry giant remains as a playground for graffiti artists, auto scrappers, and paintball warriors.

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

This sprawling bookstore spans four floors and has more than a million books in stock.

The only subway station in the city that still makes use of gap fillers.

Elaborate tile work in this railway station tells the story of Portugal.

Ancient catacombs form the foundation for this Rococo orgy of a church.

A hidden three-foot-wide house separates these two regal churches.

This restored Portuguese cafe may well be the most beautiful place in the world to grab a Big Mac.

The stunning interior of this Gothic church is covered in ornate gold details.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

The mummified right fist of a 1,000-year-old saint-king sits inside an ornate golden reliquary.

This landmark cemetery in Boston was created more than 300 years ago.

A remnant from the golden age of aviation still in use today, Pan Am's Clipper service took off from this Art Deco gem.

The dairy farm in upstate New York where nearly half a million people gathered for three days of peace and music in 1969.

Once a popular watering hole among longshoremen and shipyard workers, this neighborhood treasure spans more than 100 years of Red Hook history.

A little lighthouse in New York City, surrounded by mysterious stories of insanity-driven construction.

The rough and tumble president's childhood home displays the shirt he was once shot in and the speech that saved him.

The fanciest public restroom in New York City boasts fresh flowers, art, and a classical music soundtrack.

The oldest surviving bridge in New York City, which reopened to pedestrians in 2015.

It wouldn't be long after purchasing this farm, Brown would lead his siege on Harper's Ferry.

The only statue of its kind to commemorate Washington's beginnings as an officer of the British Colonial Militia.

The singer, actor, and activist lived here during his final years, and now it’s a museum dedicated to his legacy.

The Master of Magnetism dominates the walls of a scrap metal yard to keep graffiti artists at bay.