John Wayne Gacy, infamously known as the "Killer Clown," is one of the most chilling serial killers in US history. Gacy was convicted of murdering at least 33 young men and boys during the 1970s. His grisly crimes were discovered when the body of 15-year-old Robert Piest led investigators to his suburban Chicago home. Gacy’s victims were often lured with promises of work, only to be overpowered, tortured, and killed. His trial in 1980 captivated the nation, and he was sentenced to death, ultimately executed in 1994.