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.

The deepest lake in the United States, and once the site of epic destruction that lives on in legends.

The world's longest known cave system.

The first declared National Monument in the United States.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

The world's largest mountain carving could fit all of Mount Rushmore inside it many times over.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

The site of Paul Revere's historic two lantern warning.

Mrs. Mallard and her brood are a beloved fixture in Boston Public Garden.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

A museum dedicated to the history and exploration of both popular music and science fiction.

Yo, Adrian!

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

A wonderful display of arts and crafts handmade by local artisans in the Southern Appalachians.

The first home and studio that belonged to the famous architect.

This whimsical Oz-themed park had a wonderful impact on the surrounding neighborhood.

Chicago's Navy Pier on Lake Michigan was a training hub for aircraft carrier pilots during WWII.

This museum celebrating the almighty dollar lets visitors literally stand in the shadow of a million bucks.

At Chicago's revered Field Museum, visitors are invited to learn about and literally explore DNA.

This awkward aquarium sculpture is one of the strangest statues in Chicago.

A spiritual vortex among the red rocks in Sedona.

A bizarre house filled with an astounding array of collections.