12. Star Trek: Deep Space Nine - Season 5 Finale (A Call To Arms)
The fifth season finale of Star Trek: Deep Space Nine took the show in a thrilling new direction. The cold war with the Dominion that had been growing since the end of season two finally exploded into all out war, leading to an epic-two year galactic conflict that changed how audiences saw Star Trek forever. It was a thrilling cliffhanger. Captain Sisko blockades the worm hole to stop more Dominion ships from the Gamma Quadrant joining the Cardassians. Ignoring his enemy's protests, he then faces an invasion of Jem'Hadar and Cardassian forces that results in the shocking loss of Deep Space Nine and the villainous Gul Dukat once again in charge of the station. It also started the Dominion War, with the Defiant joining a massive fleet of Federation and Klingon ships, the like audiences had never seen before. Star Trek: Deep Space Nine kept the promise of that thrilling cliffhanger with season six's Sacrifice Of Angels and beyond and made this Star Trek the show to watch.