The 5 best "Star Trek" episodes were aired between 1966 and 1969, and were followed by numerous sequels. In the beginning the show was not popular and was constantly under the threat of cancellation. It was not until the show went to syndication that it suddenly became wildly popular and became a phenomenon with the popular culture also known as "trekkies." Below are the best "Star Trek" episodes.
- "City on the Edge of Forever" - Awarded the 1968 Hugo Award, "City on the Edge of Forever" is one of the best "Star Trek" episodes. Dr. McCoy accidently alters history when the crew of the USS Enterprise discovers a portal through space and time and end up in Depression-era New York. They meet a social worker played by Joan Collins who causes the nations involvement in World War II to be delayed and the Nazi's win the war and conquer the world.
- "Mirror Mirror" - Broadcast in 1967, "Mirror Mirror" is one of the best "Star Trek" episodes. The concept of the Mirror Universe is introduced in this episode. A transporter mistake exchanges Captain Kirk and companions with their evil counterparts in a parallel universe. The Enterprise becomes an evil ship of the Terran Empire.
- "Space Seed" - Famous for later becoming "Star Trek II: The Wrath of Khan," "Space Seed" is one of the best "Star Trek" episodes. The Enterprise awaken a powerful dictator from suspended animation. The awakened crew are genetically-enhanced supermen from the Eugenics War in the 1990's which was led by Khan Noonien Singh, played by Ricardo Montalban.
- "Arena" – Broadcast in 1967, "Arena" is one of the best "Star Trek" episodes. This was the first episodes to introduce the Gorn. Captain Kirk pursues an unknown enemy for an unprovoked attack. Unarmed, Kirk must battle the Gorn outside of the Enterprise with only his survival instincts and wit. A battle ensues but Kirk and his enemy become friends and the universe is saved.
- "This Side of Paradise" – Another one of the best episodes of "Star Trek" is "This Side of Paradise." The Enterprise visit a planet where the occupants are all under the influence of a strange plant. Spock is given the main role as the Vulcan who has feelings, even though Vulcan's do not have feelings. The entire crew becomes drugged by the spores of the plants but Captain Kirk manages to save his crew and the emotional Spock.