The Chicago Tribune's archives reveal that in 1967, at least 10 tornadoes touched down in northern Illinois, killing at least 58 people and injuring over 1,000. The Lager Beer Riot in 1855, which resulted in a 600 percent increase in tavern license fees and Sunday closings, was considered Chicago's first civil disturbance. In 1955, twins Deborah Marie and Christine Mary Andrews were successfully separated during a five-hour surgery. The Chicago Bulls won their fourth NBA championship in six years in 1996, beating the Seattle SuperSonics 87-75. In 2015, Heather Mack and boyfriend Tommy Schaefer were convicted in the slaying of Sheila von Wiese-Mack, receiving an 18-year prison term.