1. Teri Dies
Its the end of the first season. The assassination of Senator Palmer was foiled. Jacks wife and daughter are safe. Then Nina Myers begins to make her escape and one of the most shocking season finales of modern television history began to take shape. Game of Thrones and many other shows have tried to pull a similar trick but few have succeeded in leaving an impression as large as this did. There are so many big TV productions today that it's hard to remember that back in the winter of 2001 television series did not combine complex story arcs and film-quality special effects with powerful actors as shows do today. This was ground breaking television. Only minutes before Jack Bauer was the hero and it seemed he had earned a happy ending. But Jack and the audience learned a valuable lesson. There is hardly ever good news in 24 without a consequence. By the end of the episode Jack is hunched over the body of his dead wife. A broken man.
Honourable Mention: The Cougar
Even with so much going on, twenty four hours of television is a long time to fill. As a result, many of the show's subplots and cliff-hangers were less than brilliant. (Teris amnesia, Chase's baby and Kyle Singer to name a few) But this one became notorious among fans. Jacks daughter, Kim, had been arrested after escaping from her violent boss in his car. The police caught her in the stolen vehicle and then found a dead body in the boot. After a road accident Kim was able to escape police custody and found herself out alone in the woods. As the night starts to close in, what should confront her? A Cougar. Petrified she runs and gets caught in a snare. Jacks irritating daughter looks doomed. Split screen. Scared Kim. Confused Cougar. The ultimate stand-off.