Circa 2076, 82 civilian Nakans were massacred by a military unit in the area in which the monument was situated. The Nakan people built the monument as a memorial. To ensure the full horror of the incident was told, even if the monument was never seen, a synaptic transmitter was installed in it during construction. This transmitter broadcast a neurogenic signal throughout the Tarakis system that carried the memory engrams of the massacre's perpetrators. This caused anyone within range of the signal to vividly experience the massacre as if he or she had helped to commit it.
In 2376, the crew of the Federation starship USS Voyager was exposed the memorial's signal while Voyager was passing through the system. The psychological trauma the effect caused was severely debilitating. Investigating the crew's seeming participation in the massacre, Voyager's commanding officer, Captain Kathryn Janeway, ordered that Voyager be taken Tarakis, where she led an away team down to the surface. The team found the memorial, as well as the remains of some of the victims of the massacre. Janeway decided that the memorial should remain online to keep telling the story of what happened, despite objections from several of her senior officers who had experienced the signal's effect - though the ship did leave a warning beacon in orbit, so other ships would be made aware of its presence before being affected. (VOY: "Memorial")