Which episode opened CSI season 5?

The episode that opened CSI season 5 was “Viva Las Vegas.”

“Viva Las Vegas” is season 5, episode 1 of CSI: Crime Scene Investigation. It first aired on CBS on September 23, 2004, and begins the 2004–05 season with the Las Vegas crime lab investigating an unusual body found near the Area 51 boundary. The episode was directed by Danny Cannon and written by Cannon and Carol Mendelsohn.

The title is a playful reference to Las Vegas itself and to the 1964 Elvis Presley musical film Viva Las Vegas. That film is a separate work, not the CSI episode, although both use the city’s name in their titles. CSI’s episode title connects naturally to the setting while signaling the series’ blend of local spectacle and forensic investigation.

The alternatives are titles from elsewhere in the series. “Built to Kill” opens season 7, “For Warrick” opens season 9, and “Grave Danger” is the two-part season 5 finale directed by Quentin Tarantino. Season 5 ultimately contained 25 episodes, including that feature-length concluding story.