Law & Order is an American police procedural and legal drama television series, created by Dick Wolf and part of the Law & Order franchise. It originally aired on NBC and, in syndication, on various cable networks. Law & Order premiered on September 13, 1990, and completed its 20th and final season on May 24, 2010. At the time of its cancellation, Law & Order was the longest-running crime drama on American primetime television. After The Simpsons, both Law & Order and Gunsmoke tied for the second longest-running scripted primetime series with ongoing characters. Set and filmed in New York City, the series follows a two-part approach: The first half hour is the investigation of a crime (usually murder) and apprehension of a suspect by New York City Police Department homicide detectives; the second half is the prosecution of the defendant by the Manhattan District Attorney's Office.