Lost - Season 6 Episode 17 The End Everything happens for a reason.
Overview: For different reasons, Jack and the Man in Black both use Desmond to extinguish the light at the heart of the island. The island starts disintegrating, but The Man in Black is also made mortal. Still desperate to escape, The Man in Black fights Jack and mortally wounds him, but with help from Kate, Jack kills him. Realizing his destiny, Jack sacrifices himself to relight the heart of the island, so his friends can escape on the Ajira plane. Hurley takes Jack's place as protector of the island and makes Ben the new advisor. The flash sideways is revealed to be a type of limbo, or holding pattern, for the main characters, where they reside until accepting their life and death, and are then able to "let go" and "move on" together.
Comment
If I could watch only _one_ show in my life and had to choose, Lost would definitely be that one show. The only problem with Lost, is that you'll compare every show to it, for the rest of your life. It's one, if not the only, of the best tv-shows ever created. Each episode is an amazing adventure and there are so many great characters, as well as mysteries. Some hate the ending, because they don't understand it. You really have to pay attention to all the details. There is not one show or movie, that I can recommend as highly as Lost. Please make sure to watch this, it truly is a wonder and so far nothing competes.