The series was filmed in Vancouver, British Columbia, and surrounding areas and was in development for nearly ten years, as creator Kripke spent several years unsuccessfully pitching it. The pilot was viewed by an estimated 5.69 million viewers, and the ratings of the first four episodes prompted The WB to pick up the series for a full season. Originally, Kripke planned the series for three seasons but later expanded it to five. The fifth season concluded the series' main storyline, and Kripke departed the series as showrunner. The series continued on for 10 more seasons with new showrunners, including Sera Gamble, Jeremy Carver, Robert Singer and Andrew Dabb. With its eleventh season, "Supernatural" became the longest-running American live-action fantasy TV series. The series was renewed for a fifteenth and final season which consisted of 20 episodes, which premiered on October 10, 2019. The series concluded on November 19, 2020, with 327 episodes aired.