Like much great science fiction, Star Trek was often also social allegory. It predicted science and influenced generations of scientists, in effect becoming self-fulfilling prophesy.
In 1968, television networks were afraid to depict interracial relationships. The very first time a kiss between a white and black person happened on a TV show was on Star Trek, who in this case certainly did boldly go where no TV show had gone before. In the episode in question, Captain Kirk and Lieutenant Uhura were compelled to kiss by the telekinetic powers of aliens.
Today is the anniversary of the day that kiss was broadcast.
Nichelle Nichols, who played Lt. Uhura, was incredibly hot back then. If I were Captain Kirk, I would have sent a thank you note to the aliens.