The second time Chicago hosted the World's Fair, they named it "A Century of Progress" and selected a modernist "Rainbow City" aesthetic, in contrast to the previous expo's classical "White City" design. The Sky Ride, an aerial tramway suspended across two towers, quickly became the fair's most prominent attraction. Rocket-shaped cars, which emitted colorful puffs of steam, shuttled passengers across a lagoon in the fair's center. Visitors could also view the expo from the tower's observation decks, which were equipped with coin-operated telescopes. Historians estimate that up to 4.5 million people rode the Sky Ride before it was taken down after the fair's closing.
Read the full story in "'Rocket' Cars to Run at World's Fair"