The Galactic Barrier is a celestial location which is featured in the Star Trek multimedia franchise. It appeared in the original NBC television series as well as the 1989 film Star Trek V: The Final Frontier. The Galactic Barrier existed on the edge o the galaxy in between the Milky Way Galaxy and the Andromeda Galaxy. Because of its high levels of radiation, most starships could not pass through it.
In the year 2268 on Stardate 4657.5, an alien race known as the Kelvans took control of the USS Enterprise with the intent of taking it through the Galactic Barrier. As the Kelvans were actually immense beings with hundreds of tentacles, they transposed their consciousness into humanoid forms. Captain James T. Kirk appealed to their new human sensitivities and convinced them to abandon this quest.
It was believed by the Vulcan zealot Sybok that the god-like entity known as Sha Ka Ree could be found at the center of the Great Barrier. Taking control of the crew of the USS Enterprise NCC-1701-A, he forced them to take him through the Galactic Barrier.