The swastika
The swastika was originally used by many Earth cultures to represent luck, the sun or reincarnation. It was used as a religious symbol by several faiths, most notably the Hindu and Buddist religions of India.
In 1920, Adolf Hitler was inspired to formally adopt the swastika as a symbol for the fascist Nazi party of Germany. The Nazis used the symbol on the party's flag, badge and armband.
When the starship Enterprise visited Ekos in 2268, Captain Kirk and Commander Spock discovered that the Ekosians had also adopted the swastika. The symbol had been introduced to the inhabitants of the planet by a Federation historian, John Gill, who had attempted to experiment with Nazism on a different test site than Earth. (TOS: "Patterns of Force")
In 2374, the swastika was used in the holodeck of the USS Voyager, a Starfleet vessel lost in the Delta Quadrant. Voyager had been captured by Hirogen hunters, who forced the crew to participate in battle simulations, including a reenactment of the Second World War, to test the crew's resilience. (VOY: "The Killing Game, Part I" and "II")
- The swastika was also used in an alternate version of 1944, when a Nazi and Na'kuhl alliance had invaded America. (ENT: "Storm Front, Part I" and "II")