The sign to a demolished amusement park now stands in front of a local library.

Chicago’s incendiary role in the labor movement.

This modest post office sits on the site of H.H. Holmes' famous murder castle.

Cold War missile launch site which has been converted to a public park.

A former atom smasher turned into an art gallery.

A unique outdoor timepiece at a "clothing-optional" resort.

Arguably the best example of an authentic Dutch windmill in the United States, rivaling its counterparts in the Netherlands.

World's second largest particle accelerator, where nature reveals its secrets.

This rare female version of the Muffler Man has its clothes removed each summer to signal the start of pool season.

These Depression-era WPA sculptures have made a couple of stops over the years.

A collection of 11 million buttons illustrates the human toll of the Holocaust.

This historic Illinois "Muffler Man" has been converted from axe-touting lumberjack to rocket-wielding space ace.

The carved remains of a 200-year-old oak tree memorialize the namesake of the iconic "Wizard of Oz" character.

Formerly the world's largest, this Willy Wonka-esque contraption runs 24/7.

These banned cigarette vending machines now sell little pieces of pocket-sized art.

Once one of the world's great cities, Cahokia was a place of religious worship, trade and mass human sacrifice before being mysteriously abandoned.

An abandoned meat mecca now serves as an excellent locale for urban exploration.

The red brick house where the father of rock 'n' roll wrote some of his classic hits.

A plaque on the side of a parking garage marks the burial place of a great Ottawa chief.

What was once a presidential estate is now an exotic menagerie and home to the Budweiser Clydesdales.

A big museum full of little worlds.

University City's quirkiest resident lives in a park named after its first.

A chessmaster's dream destination.

In a historic steel foundry east of the Mississippi River, thousands of wooden crates hold the architectural remnants of buildings long gone but not forgotten.