A small metropolis of Pueblo cave dwellings have been carved right into the hillside of this national monument.

Twice a year, visitors can tour the desolate site that birthed the Atomic Age.

Legends surround this jagged rock formation in the New Mexico desert.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

The world's longest known cave system.

This museum in the woods evokes the work and lives of Michigan's 19-century lumberjacks.

This observatory comes complete with three separate telescopes and a dedicated community of amateur and expert astronomers.

These sprawling mines once served as a source of plaster and today serve as a storage facility.

The fifth-longest suspension bridge the world, connecting one Michigan peninsula to another.

World's largest Christmas store.

An angular maze of concrete in Grand Rapids acts both as public art and as a staircase for fish traveling upstream.

A charming remnant of 19th-century fishing towns sits on Michigan’s Leelanau Peninsula.

A sealed test tube said to hold Thomas Edison's dying breath was given to the inventor's friend and mentee, Henry Ford.

The park is home to the United States's only still-operating Dutch windmill.

This shallow cave got its name from copious amount of human bones found inside.

Island where motor vehicles are banned -- home to the only carless highway in the United States.

Strange physical sensations and optical contradictions keep visitors coming back for more.

This national park on the shore of Lake Michigan features remarkable dunes that lie at the heart of a Chippewa legend.