The Griswold family was on their way to Disneyland when they decided to stop off in Chicago for the fireworks at Navy Pier.  Clark had the large grill in the back of the station wagon with a cooler filled with sausages from Milwaukee.  They were clever to cordon off their private space using trash and recycling containers provided by the Chicago Park District and some left over crime scene yellow tape.  The actual show started at 9:30 pm but Clark had some of his own fireworks from a visit to Indiana where he gassed up the car (less tax).  By morning they had packed up and were taking US 66 to California.