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

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

Shop of curiosities with a dinosaur museum tucked in its basement.

A hot dog stand where the heads are just as hot as the dogs.

This alley in downtown Chicago held the bodies of over 600 people after the fateful Iroquois Theatre fire.

An outdoor urban gallery of large-scale artworks by the world's most influential street artists.

One of the largest pieces of scientific equipment ever carried on a NASA space shuttle sits in a Chicago alley.

An unassuming store hides relics of its former life as the jazz club that hosted some of the best black performers of the 1920s and '30s.

This morbid, delightful curiosity shop offers everything from animal bones to human teeth.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

A century-old network of freight tunnels underneath the city's historic business district.

This shop for all your super spy needs hides an educational secret.

Not to be confused with the iconic New York City skyscraper, this Chicago building is a vibrant hub for artists.

A Bibliophile's Dream.

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

Hot Doug's "Hot Dog" Stand.

Former meatpacking facility turned vertical farm and sustainable business complex.

These abandoned grain silos and tunnels are an urban exploration dream.

A lush green oasis in the middle of Chicago.

Half-sized replica of the Leaning Tower of Pisa built to honor Galileo.

The world's largest talking cow would like to tell you about the benefits of 100% Wisconsin dairy products, if only she still could.

Taxidermy, Cigar Store Indians, A Model of a New York Tenement and Delicious Draft Root Beer.

The clothes-washing king doubles as a community center with some unusual features, including an aviary filled with finches.

This sprawling mini-golf empire is an impressive testament to a disappearing attraction.