"City on the Edge of Forever" (also known as "Flashbacks") is the seventh episode of the second season of the American animated television series South Park. The 20th episode of the series overall, it originally aired on Comedy Central in the United States on June 17, 1998. The episode was written by series co-creator Trey Parker, along with Nancy M. Pimental, and directed by Parker. It guest stars Henry Winkler, Jay Leno, and Brent Musburger. In the episode, the boys reminisce about past experiences as their school bus is left teetering on the edge of a cliff. Ms. Crabtree leaves to seek help, but forgets about the children when she meets a truck driver named Marcus.