These Great Lakes sea caves accessible by boat in the summer turn into temples of ice reachable by foot in the winter.

Funhouse of found art and participatory sculpture.

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

This missionary's legacy looms large over the Upper Peninsula of Michigan—literally.

One of the largest crucifixes in the world stands 55 feet tall in a secluded, wooded area of northern Michigan.

Large one-man sculpture park in Michigan.

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

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

A bizarre house filled with an astounding array of collections.

A painted-over wall in Detroit originally built to segregate a black community from an adjacent white development.

One man's attempt to create an artistic wonder on a run-down block in Detroit.

Hell on Earth is actually a small town in Michigan where anyone can be mayor for a day.

A bronze monument to Cleveland's favorite, fastest son.

The world's longest known cave system.

Andy Griffith's hometown has made itself up to look like the fictional town of Mayberry.

The U.S. Supreme Court's secret Cold War relocation facility in the mountains of North Carolina.

A piece of outsider public art accompanied by a strange urban legend.

I-95's Tijuana-style celebration of kitsch at the Carolina border.

This psychedelic tromp l'oeil seems to be beckoning drivers to crash into a wall.

South Carolina's last remaining slavery auction house is now a museum devoted to its own tragic history.

A restored, one-room African-American schoolhouse in the diva's hometown now preserves the legacy of its most famous student.

Every day a troupe of pampered water fowl walk the red carpet to their favorite fountain.

The hotel where Martin Luther King Jr. was shot is now a museum dedicated to his work.

The secret city built by the Manhattan Project.