One of the few working locomotive roundhouses in the United States.

The only surviving prototype for Buckminster Fuller's house of the future.

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

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

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

Two dozen rescued bears roam (mostly) free at the largest bear ranch in the U.S.

This lighthouse and shipwreck museum keep a torch burning for the memory of the SS Edmund Fitzgerald.

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

These pretty kitties killed and ate as many as 135 railway workers.

Often referred to as the largest spring in America.

The deepest spring in Missouri.

A historic, scenic mill that was forced to close due to overlogging.

An average of 33 million gallons of water pour out of the collapsed cave at the heart of this spherical spring.

Where the author wrote her beloved "Little House" books.

The Old Courthouse takes visitors on a captivating trip through St. Louis' timeline.

What was meant to be a temporary exhibit is now a permanent fixture at the St. Louis Zoo filled with beautiful birds.

A piece of John the Baptist in the American heartland.

Four, 18-foot-tall badminton shuttlecocks lie scattered about the lawn of a Kansas City museum.

This historic cliffside mansion uses a natural cave for air conditioning.

A geological oddity formed by two rivers carving out a mass of limestone on both sides.

Two Ming Dynasty lion statues guard the entrance to the journalism school.

The iconic remains of the original Academic Hall that burned down in 1892.