This was supposed to be something else, but they couldn't afford it. Wikipedia:

The Century of Progress Exposition committee sought an exciting signature attraction, one that would be remembered like the Eiffel Tower from the 1889 Paris World's Fair or the Ferris wheel of the 1893 Chicago World's Fair. One proposal under consideration, to be underwritten by Montgomery Ward, was called the Tower of Water and Light—a 250-foot-tall tower with water flowing down the outside and elevators traveling to observation platforms.

When the Montgomery Ward company backed out of its offer to finance the tower, the commission considered the Sky Ride.

Dynamited when the fair was over.